TWI751275B - Compounds and liquid-crystalline medium - Google Patents

Abstract

The invention relates to compounds of the formula I, and to a liquid-crystalline medium, preferably having a nematic phase and negative dielectric anisotropy, which comprises a) one or more compounds of the formula I

and b) one or more compounds of the formula II

and/or c) one or more compounds selected from the group of the compounds of the formulae III-1 to III-4 and B

Description

Compounds and liquid crystal media

The present invention relates to novel compounds, in particular novel compounds for use in liquid crystal media, and the use of such liquid crystal media in liquid crystal displays, and such liquid crystal displays, in particular for the use of negative dielectrics in vertical initial alignment A liquid crystal display that uses the ECB (Electrically Controlled Birefringence) effect of liquid crystals. The liquid-crystal media according to the invention are distinguished by the extremely short response times simultaneously with the high voltage holding ratio (VHR or just HR for short) in the displays according to the invention.

作為穩定劑，在例如WO 2009/129911 A1及WO 2012/076105 A1中提出。然而，相應液晶混合物不具有用於一些實際應用之充分特性。尤其是，其對於使用典型CCFL(冷陰極螢光燈)以及特定言之典型現代LED (發光二極體)背光的照射而言不夠穩定。 自例如EP 2 182 046 A1、WO 2008/009417 A1、WO 2009/021671 A1及WO 2009/115186 A1已知類似液晶混合物。然而，其中未指出使用穩定劑。 根據本文中之揭示內容，此等液晶混合物亦可視情況包含各種類型之穩定劑，諸如酚類及位阻胺(受阻胺光穩定劑，簡稱HALS)。然而，此等液晶混合物特徵在於相對高之臨限電壓及至多中等之穩定性。特定言之，其電壓保持率在曝光之後降低。另外，通常發生淡黃色變色。 在液晶介質中使用多種穩定劑描述於例如JP (S)55-023169 (A)、JP (H)05-117324 (A)、WO 02/18515 A1及JP (H) 09-291282 (A)中。 EP 2 993 216 A1尤其提出下式之化合物

用於穩定介電正性液晶介質。 WO 2009/129911 A1提出化合物

， 除氮雜環化合物以外的其他若干穩定劑作為第二穩定劑用於穩定介電負性液晶介質。 EP 2 514 800 A2提出下式之化合物的用途

及

其中除其他含義之外，R¹¹ 亦可為O^. 或OH，但不為H，用於液晶介質中的穩定目的。然而，此等化合物關於水解之化學穩定性及特定言之其在液晶介質中之溶解度在大多數情況下不適於實際應用。 WO 2016/146245 A1提出下式之化合物

用於液晶介質中的穩定目的。此化合物以及以下化合物

亦在DE 2016 005 083 A1中提出用於液晶介質中的穩定目的。然而，在此等化合物之情況下尤其關於水解之化學穩定性及尤其在液晶介質中的溶解度在大多數情況下不適於實際應用。 下式之醚連接之化合物

在尚未公開之申請案DE 10 2016 009485.0中提出用作液晶混合物的穩定劑。 具有相應低定址電壓的先前技術的液晶介質具有相對低的電阻值或低VHR，且通常導致顯示器中非所需的閃爍及/或不充分的透射。另外，其對於加熱及/或UV曝露不夠穩定，至少若其具有相應高極性(對於低定址電壓為必要的)。 另一方面，具有高VHR的先前技術之顯示器之定址電壓通常過高，對於不直接或不連續連接至電力供應器網絡之顯示器，諸如，用於行動應用之顯示器尤其如此。 另外，液晶混合物之相範圍必須足夠寬以用於顯示器之預期應用。因此，單元中的及較佳在-30℃下的本體中的低溫儲存穩定性應為240小時或更久。 必須改良(亦即減小)顯示器中之液晶介質之響應時間。此對於用於電視或多媒體應用之顯示器尤其重要。為改良響應時間，過去已反覆地提出優化液晶介質之旋轉黏度(γ₁ )，即獲得具有最低可能旋轉黏度之介質。然而，此處實現之結果不適於許多應用且因此需要進一步發現優化方法。 該介質對於極端負荷，尤其對於UV曝光及加熱之適當穩定性極為重要。在同時優化旋轉黏度的情況下，此尤其困難。特定言之，在應用於行動設備(諸如行動電話)的顯示器中的情況下，此可能是至關重要的，因為尤其在此等裝置的情況下，較佳使用相對低的定址頻率。 迄今所揭示之MLC顯示器之缺點由於其比較低的對比度，相對高之視角依賴性及難以出現灰度，以及其不適當之VHR及其不足的壽命。 因此，仍持續十分需要具有極高比電阻，同時具有較大工作溫度範圍、較短回應時間及較低臨限電壓之MLC顯示器，藉助於該等顯示器，可產生各種灰度，且該等顯示器尤其具有良好且穩定的VHR。The principle of electrically controlled birefringence, the ECB effect or the DAP (Deformation of Alignment Phase) effect was first described in 1971 (MF Schieckel and K. Fahrenschon, "Deformation of nematic liquid crystals with vertical orientation in electrical fields", Appl. Phys. Lett. 19 (1971), 3912). Subsequent papers by JF Kahn (Appl. Phys. Lett. 20 (1972), 1193) and G. Labrunie and J. Robert (J. Appl. Phys. 44 (1973), 4869). J. Robert and F. Clerc (SID 80 Digest Techn. Papers (1980), 30), J. Duchene (Displays 7 (1986), 3) and H. Schad (SID 82 Digest Techn. Papers (1982), 244) The paper shows that the liquid crystal phase must have high elastic constant K ₃ /K ₁ ratio, high optical anisotropy Δn value and dielectric anisotropy value Δe≤-0.5 in order to be suitable for high information display devices based on the ECB effect. Electro-optic display elements based on the ECB effect have vertical edge alignment (VA technology = Vertically Aligned or VAN = Vertically Aligned Nematic). Dielectrically negative liquid crystal media can also be used in displays using the so-called IPS (in-plane switching) effect. The industrial application of this effect in electro-optical display elements requires an LC phase, which must meet various requirements. Of particular importance here is the chemical resistance against moisture, air and physical influences, such as heat, radiation in the infrared, visible and ultraviolet regions, and direct and alternating electric fields. In addition, a commercially available LC phase needs to have a liquid crystal mesophase at a suitable temperature range and at a low viscosity. None of the series of compounds with liquid crystal mesophases disclosed so far includes a single compound that satisfies all of these requirements. Typically a mixture of two to 25, preferably three to 18, compounds is prepared to obtain material that can be used as the LC phase. Matrix liquid crystal displays (MLC displays) are known. Non-linear elements that can be used for individual conversion of individual pixels are, for example, active elements (ie, transistors). The term "active matrix" is then used, in which thin film transistors (TFTs) are typically utilized, which are typically arranged on a glass plate as a substrate. A distinction is made between two technologies: TFTs contain compound semiconductors, such as CdSe, or TFTs are based on polycrystalline and especially amorphous silicon. The latter technology currently has the greatest commercial value worldwide. A TFT matrix is applied to the inside of one glass plate of the display, while the other glass plate carries transparent counter electrodes inside it. Compared to the size of the pixel electrode, the TFT is extremely small and has little adverse effect on the image. This technique can also be extended to fully colour-capable displays, where a mosaic system of red, green and blue filters is arranged in such a way that the filter elements are opposite each switchable pixel. The most commonly used TFT displays to date typically operate with crossed polarizers for transmission and are backlit. For TV applications, IPS cells or ECB (or VAN) cells are used, while monitors typically use IPS cells or TN (twisted nematic) cells, and notebook, laptop, and mobile applications typically use TN cells. The term MLC display here covers any matrix display with integrated non-linear elements, ie in addition to the active matrix the display also has passive elements, such as varistors or diodes (MIM=metal-insulator-metal). MLC displays of this type are particularly suitable for TV applications, monitors and notebook computers, or for displays with high information density, such as in automobile construction or aircraft construction. In addition to the issues regarding the angular dependence of the contrast ratio and the response time, difficulties arise in MLC displays because the specific resistance of the liquid crystal mixture is not high enough [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E. , SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, September 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, pp. 141 and below, Paris; STROMER, M., Proc. Eurodisplay 84, September 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, pp. 145 et seq., Paris]. As the resistance decreases, the contrast ratio of the MLC display deteriorates. High (initial) resistance is extremely important for displays that must have acceptable resistance values over long periods of operation, as the specific resistance of liquid crystal mixtures typically decreases over the life of an MLC display due to interaction with the inner surface of the display. Except for IPS displays (eg Yeo, SD, Paper 15.3: "An LC Display for the TV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pages 758 and 759) and long-known TN displays In addition, displays using the ECB effect have established themselves as so-called VAN (Vertical Aligned Nematic) displays, which are one of the three recent types of liquid crystal displays that are currently most important, especially for television applications. The most important designs that can be mentioned are: MVA (Multiple Domain Vertical Alignment, eg: Yoshide, H. et al., Paper 3.1: "MVA LCD for Notebook or Mobile PCs...", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 6 to 9, and Liu, CT et al., Paper 15.1: "A 46-inch TFT-LCD HDTV Technology...", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 750-753), patterned vertical alignment (PVA; e.g. Kim, Sang Soo, Paper 15.4: "Super PVA Sets New State-of-the-Art for LCD- TV”, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 760-763) and ASV (Advanced Large View, e.g. Shigeta, Mitzuhiro and Fukuoka, Hirofumi, Paper 15.2: “Development of High Quality LCDTV”, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 754-757). In e.g. Souk, Jun, SID Seminar 2004, Seminar M-6: "Recent Advances in LCD Technology", Seminar Lecture Notes, M-6/1 to M-6/26, and Miller, Ian, SID Seminar 2004, Seminar M -7: The general forms of these technologies are compared in "LCD-Television", Seminar Lecture Notes, M-7/1 to M-7/32. Although the response time of modern ECB displays has been significantly improved by addressing methods using overdrive, eg Kim, Hyeon Kyeong et al., Paper 9.1: "A 57-in. Wide UXGA TFT-LCD for HDTV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 106 to 109, but the response time to achieve video compatibility, especially with regard to grayscale conversion, is still an unsatisfactory problem. ECB displays, such as ASV displays, use liquid crystal media with negative dielectric anisotropy (Δε), while TN and all conventional IPS displays to date use liquid crystal media with positive dielectric anisotropy. In this type of liquid crystal display, liquid crystal is used as the dielectric, the optical properties of which are reversibly changed upon application of a voltage. Since in normal displays, i.e. also in displays according to these mentioned effects, the operating voltage should be as low as possible, liquid crystalline media are used, which generally consist mainly of liquid crystalline compounds, all of which have the same dielectric anisotropy Anisotropy sign and has the highest possible value of dielectric anisotropy. In general, neutral compounds at most are used in relatively small proportions and, if possible, compounds with the opposite sign of the dielectric anisotropy to the medium are not used. In the case of liquid-crystalline media with negative dielectric anisotropy, eg for ECB displays, compounds with negative dielectric anisotropy are thus mainly used. The liquid-crystalline media employed consist essentially and substantially generally of liquid-crystalline compounds with negative dielectric anisotropy. In the media used in accordance with the present application, the largest amount of dielectrically neutral liquid crystal compounds is generally employed and generally only very little or even no dielectric positive compounds are used, since generally liquid crystal displays are intended to have the lowest possible addressing voltage. Liquid crystal media are known to be insufficiently stable for many practical applications in liquid crystal displays. In particular, it is stable to UV and even illumination with conventional backlights, resulting in especially degraded electrical properties. Thus, for example, the electrical conductivity is significantly increased. The use of so-called "Hindered Amine Light Stabilizers", or HALS for short, has been proposed to stabilize liquid crystal mixtures. Nematic liquid crystal mixture with negative dielectric anisotropy containing small amounts of TINUVIN ^® 770, a compound of the formula

Stabilizers are proposed, for example, in WO 2009/129911 A1 and WO 2012/076105 A1. However, the corresponding liquid crystal mixtures do not have sufficient properties for some practical applications. In particular, it is not stable enough for illumination using typical CCFL (cold cathode fluorescent lamps) and in particular typical modern LED (light emitting diode) backlights. Similar liquid crystal mixtures are known from eg EP 2 182 046 A1, WO 2008/009417 A1, WO 2009/021671 A1 and WO 2009/115186 A1. However, the use of stabilizers is not indicated therein. According to the disclosure herein, these liquid crystal mixtures may also optionally contain various types of stabilizers, such as phenols and hindered amines (Hindered Amine Light Stabilizers, or HALS for short). However, these liquid crystal mixtures are characterized by relatively high threshold voltages and at most moderate stability. Specifically, its voltage holding ratio decreased after exposure. In addition, yellowish discoloration usually occurs. The use of various stabilizers in liquid crystal media is described, for example, in JP (S) 55-023169 (A), JP (H) 05-117324 (A), WO 02/18515 A1 and JP (H) 09-291282 (A) . EP 2 993 216 A1 proposes in particular compounds of the formula

Used to stabilize dielectrically positive liquid crystal media. Compounds proposed in WO 2009/129911 A1

, In addition to nitrogen heterocyclic compounds, several other stabilizers are used as second stabilizers to stabilize the dielectrically negative liquid crystal medium. EP 2 514 800 A2 proposes the use of compounds of the formula

and

Wherein in addition to other meanings, R ¹¹ may also be ^O. Or OH, but is not H, for the purpose of stabilizing the liquid crystal medium. However, the chemical stability of these compounds with respect to hydrolysis and in particular their solubility in liquid-crystalline media is in most cases unsuitable for practical use. WO 2016/146245 A1 proposes compounds of the following formula

For stabilization purposes in liquid crystal media. This compound and the following compounds

Also proposed in DE 2016 005 083 A1 for stabilization purposes in liquid-crystalline media. In the case of these compounds, however, the chemical stability, especially with regard to hydrolysis, and the solubility, especially in liquid-crystalline media, are in most cases unsuitable for practical use. ether-linked compounds of the formula

Use as stabilizer for liquid crystal mixtures is proposed in the as-yet unpublished application DE 10 2016 009485.0. Prior art liquid crystal media with correspondingly low addressing voltages have relatively low resistance values or low VHRs and often result in undesirable flicker and/or insufficient transmission in the display. Additionally, it is not stable enough to heating and/or UV exposure, at least if it has a correspondingly high polarity (necessary for low addressing voltages). On the other hand, the addressing voltages of prior art displays with high VHR are often too high, especially for displays that are not directly or discontinuously connected to a power supply network, such as displays used in mobile applications. Additionally, the phase range of the liquid crystal mixture must be broad enough for the intended application of the display. Therefore, the low temperature storage stability in the unit and preferably in the bulk at -30°C should be 240 hours or more. The response time of liquid crystal media in displays must be improved (ie reduced). This is especially important for displays used in television or multimedia applications. In order to improve the response time, it has been repeatedly proposed in the past to optimize the rotational viscosity (γ ₁ ) of the liquid crystal medium, ie to obtain the medium with the lowest possible rotational viscosity. However, the results achieved here are not suitable for many applications and therefore further optimization methods need to be discovered. Proper stability of the medium to extreme loads, especially UV exposure and heating, is extremely important. This is especially difficult in the case of simultaneous optimization of rotational viscosity. In particular, in the case of applications in displays of mobile devices, such as mobile phones, this may be critical, as relatively low addressing frequencies are preferably used, especially in the case of such devices. Disadvantages of the MLC displays disclosed so far are their relatively low contrast ratio, relatively high viewing angle dependence and difficulty in gray scale, as well as their inappropriate VHR and their insufficient lifetime. Therefore, there continues to be a great need for MLC displays with extremely high specific resistance, at the same time having a larger operating temperature range, shorter response time and lower threshold voltage, by means of which various grayscales can be generated, and which displays Especially with good and stable VHR.

The object of the present invention is to provide MLC displays based on the ECB effect, the IPS effect or the FFS (Fringe Field Switching) effect, not only for monitor and TV applications, but also for mobile phones and navigation systems, as described in Lee, SH, Lee, SL & Kim, HY "Electro-optical characteristics and switching principle of nematic liquid crystal cell controlled by fringe-field switching", Appl. Phys. Letts., Vol. 73, Issue 20, pp. 2881-2883 (1998), does not have the above-mentioned disadvantages, or only has the disadvantages to a lesser extent, and at the same time has a very high specific resistance value. In particular, for mobile phones and navigation systems, it must be ensured that they also operate at extremely high and extremely low temperatures. Unexpectedly, it has been found to be useful in such display elements comprising a nematic liquid crystal mixture of at least one compound of formula I and in each case at least one compound of formula II, preferably a compound of sub-formula II-1, and /or at least one compound selected from the group of compounds of formulae III-1 to III-4, preferably compounds of formula III-2, and/or compounds of formula B, it is possible to achieve a low threshold voltage and a short response Relatively low birefringence (Δn), good decomposition stability to heat and exposure to UV, good solubility, and stable high VHR liquid crystal displays, especially FFS displays, while at the same time a sufficiently broad nematic phase is favorable. Media of this type can be used in particular for electro-optical displays with active matrix addressing based on the ECB effect and for IPS displays and for FFS displays. The invention therefore relates to liquid-crystalline media based on mixtures of polar compounds comprising at least one compound of formula I and containing one or more compounds of formula II and preferably another one or more selected from formulae III-1 to III-4 and/or formulae At least one compound of the compounds of B. The mixtures according to the invention exhibit a very wide range of nematic phases at clearing points ≥ 70°C, with very favorable capacitance thresholds, relatively high retention values and good low temperatures at both -20°C and -30°C stability, and very low rotational viscosity. In addition, the mixtures according to the invention are distinguished by a good ratio of clear point and rotational viscosity and by a high negative dielectric anisotropy. Unexpectedly, it has now been found that it is possible to achieve liquid crystalline media with suitably high Dε, suitable phase ranges and Dn, which do not have the disadvantages of prior art materials, or at least only have them to a greatly reduced degree. Surprisingly, it has been found here that the compounds of formula I, even when no additional thermal stabilizer is used alone, in many cases result in significant stabilization of liquid crystal mixtures both to UV exposure and also to heat. This is especially true in most cases where the parameter p in the compound of formula I used represents 2 and n*p represents 4 or 6. In one embodiment of the invention, compounds of the formula I in which p represents 2 and n represents 3 or 4 are therefore particularly preferred, and the precise use of these compounds in liquid crystal mixtures according to the invention is especially preferred. Compounds of formula I are likewise preferred, wherein the group -Z ¹¹ -S ¹¹ -Z ¹² - represents an ω-bisoxyalkylene group, ie -OS ¹¹ -O-. Specifically, however, sufficient stabilization of the liquid crystal mixture to both UV exposure and sandwiching can also be achieved in the presence of one or more other compounds, preferably phenolic stabilizers, in the liquid crystal mixture in addition to the compound of formula I. These other compounds are suitable as thermal stabilizers.

其中 R¹¹ 在每次出現時彼此獨立地表示H、F、具有1-20個C原子的直鏈或分支鏈烷基鏈，其中一個-CH₂ -基團，或若存在複數個-CH₂ -基團可置換為-O-或-C(=O)-，但兩個相鄰-CH₂ -基團不可置換為-O-，且一個或若存在的複數個-CH₂ -基團可置換為-CH=CH-或-C≡C-，且其中一個H原子或複數個H原子可置換為F、OR¹³ 、N(R¹³ )(R¹⁴ )或R¹⁵ ， R¹¹ 較佳表示H或烷基，尤其較佳烷基，特別較佳正烷基且極佳正丁基， R¹² 在每次出現時彼此獨立地表示具有1-20個C原子的直鏈或分支鏈烷基鏈，其中一個-CH₂ -基團或複數個-CH₂ -基團可置換為-O-或-C(=O)-，但兩個相鄰-CH₂ -基團不可置換為-O-；含有環烷基或烷基環烷基單元且其中一個-CH₂ -基團或複數個-CH₂ -基團可置換為-O-或-C(=O)-，但兩個相鄰-CH₂ -基團不可置換為-O-，且其中一個H原子或複數個H原子可置換為F、OR¹³ 、N(R¹³ )(R¹⁴ )或R¹⁵ 的烴基；或芳族或雜芳族烴基，其中一個H原子或複數個H原子可置換為F、OR¹³ 、N(R¹³ )(R¹⁴ )或R¹⁵ ， R¹² 較佳表示H、未分支烷基或分支鏈烷基，尤其較佳H或未分支烷基， R¹³ 在每次出現時彼此獨立地表示具有1至10個C原子的直鏈或分支鏈烷基或醯基，較佳正烷基，或具有6-12個C原子的芳族烴或羧酸基， R¹⁴ 在每次出現時彼此獨立地表示具有1至10個C原子的直鏈或分支鏈烷基或醯基，較佳正烷基，或具有6-12個C原子的芳族烴或羧酸基，較佳地其限制條件為，在N(R¹³ )(R¹⁴ )之情況中，視情況存在醯基， R¹⁵ 在每次出現時彼此獨立地表示具有1至10個C原子的直鏈或分支鏈烷基，其中一個-CH₂ -基團或複數個-CH₂ -基團可置換為-O-或-C(=O)-，但兩個相鄰-CH₂ -基團不可置換為-O-， S¹¹ 及S¹² 在每次出現時彼此獨立地表示具有1至20個C原子的伸烷基，其為分支鏈或較佳直鏈，較佳具有1-20個C原子，較佳具有1-10個C原子，尤其較佳具有1至6個C原子的-(CH₂ -)_n ，其中一個-CH₂ -基團或若存在的複數個-CH₂ -基團可置換為-O-或-C(=O)-，但兩個相鄰-CH₂ -基團不可置換為-O-，且一個或若存在的複數個-CH₂ -基團可置換為-CH=CH-或-C≡C-，且其中一個H原子或複數個H原子可置換為F、OR¹³ 、N(R¹³ )(R¹⁴ )或R¹⁵ ，或表示單鍵， X¹¹ 表示C， Y¹¹ 至Y¹⁴ 各自彼此獨立地表示甲基或乙基，尤其較佳全部表示甲基或乙基中之任一者，且極佳甲基， Z¹¹ 至Z¹⁴ 在每次出現時彼此獨立地表示-O-、-(C=O)-、-O-(C=O)-、-(C=O)-O-、-O-(C=O)-O-、-(N-R¹³ )-、-N-R¹³ -(C=O)-或單鍵，若S¹¹ 為單鍵，但Z¹¹ 及Z¹² 皆不同時表示-O-，且然而若S¹² 為單鍵，則Z¹³ 及Z¹⁴ 皆不同時表示-O-， Z¹¹ 較佳表示-O-， Z¹³ 較佳表示單鍵， p 表示1或2，較佳2， o 表示(3-p)，以及 若p為2， 則n 表示整數2至4，較佳2或3，尤其較佳3，及 m 表示(4-n)，以及 若p為1， 則n 表示整數3至10，較佳4至8，尤其較佳4或6，以及 m 表示(10-n)，以及

且其中在p = 1之情況中，-X¹¹ [-R¹¹ ]_o -亦可替代地表示單鍵， 及 b) 一或多種式II化合物

其中 R²¹ 表示具有1至7個C原子的未經取代之烷基或具有2至7個C原子的未經取代之烯基，較佳為正烷基，尤其較佳具有3、4或5個C原子，及 R²² 表示具有2至7個C原子，較佳具有2、3或4個C原子的未經取代之烯基，更佳乙烯基或1-丙烯基，且尤其乙烯基， 及/或 c) 選自式III-1至III-4，較佳式III-2，及式B之群的一或多種化合物，

其中 R³¹ 表示具有1至7個C原子的未經取代之烷基，較佳正烷基，尤其較佳具有2至5個C原子， R³² 表示具有1至7個C原子，較佳具有2至5個C原子的未經取代之烷基，或具有1至6個C原子，較佳具有2、3或4個C原子的未經取代之烷氧基，及 m、n及o 各自彼此獨立地表示0或1， R^B1 及R^B2 各自彼此獨立地表示具有1至7個C原子的未經取代之烷基、烷氧基、氧雜烷基或烷氧基烷基，或具有2至7個C原子的烯基或烯基氧基，及 L^B1 及L^B2 各自彼此獨立地表示F或Cl，較佳F。 在式I化合物中，基團N(R¹³ )(R¹⁴ )較佳亦可為胺。 以下實施例為較佳的： p 為2，

在一個替代較佳實施例中， p 表示1。 在本申請案中，該等元素均包括其對應同位素。特定言之，該等化合物中之一或多個H可置換為D，且在一些實施例中，此亦為尤其較佳的。相應化合物之相應高氘化程度能夠例如偵測及識別該等化合物。在一些情況下，此為極有幫助的，在式I化合物之情況下尤其如此。 在本申請案中， 烷基 尤其較佳表示直鏈烷基，尤其CH₃ -、C₂ H₅ -、n-C₃ H₇ -、n-C₄ H₉ -或n-C₅ H₁₁ -，及 烯基 尤其較佳表示CH₂ =CH-、E-CH₃ -CH=CH-、 CH₂ =CH-CH₂ -CH₂ -、E -CH₃ -CH=CH-CH₂ -CH₂ -或E -(n -C₃ H₇ )-CH=CH-。 根據本申請案之液晶介質較佳總共包含1 ppm至2500 ppm，較佳1 ppm至1500 ppm，較佳1至600 ppm，甚至更佳1至250 ppm，較佳至200 ppm，且極佳1 ppm至100 ppm之式I化合物。 在本發明之一個較佳實施例中，在式I化合物中，

-Z¹² -S¹¹ -Z¹¹ -在每次出現時彼此獨立地表示-O-、-S¹¹ -O-、-O-S¹¹ -O-、-(C=O)-O-S¹¹ -O-、-O-(C=O)-S¹¹ -O-、-O-(C=O)-S¹¹ -(C=O)-O-、-O-S¹¹ -(C=O)-O-、-(C=O)-O-S¹¹ -C、-(C=O)-O-S¹¹ -O-(C=O)-或-(N-R¹³ )-S¹¹ -O-、-(N-R¹³ -C(=O)-S¹¹ -(C=O)-O或單鍵，較佳-O-、-S¹¹ -O-、-O-S¹¹ -O-、-(C=O)-O-S¹¹ -O-、-O-(C=O)-S¹¹ -O-或-O-S¹¹ -(C=O)-O-，及/或R¹¹ 若存在，則表示烷基、烷氧基或H，較佳H或烷基，及/或 R¹² 表示H、甲基、乙基、丙基、異丙基或3-庚基，或環己基。 在本申請案的一個較佳實施例中，在式I化合物中，

表示選自下式之基團的群

。在本申請案之一個較佳實施例中，在式I化合物中，

表示選自下式之基團之群

、

或

。 在本申請案的一個較佳實施例中，在式I化合物中，其中p較佳表示1，

在本申請案的另一較佳實施例中，在式I化合物中，基團

較佳表示選自下式之基團之群

、

、

、

或

。 在本申請案之另一較佳實施例中，其中p為2，其可與上文所述者相同或不同，在式I化合物中，

較佳表示選自下式之基團之群

及

。 在本發明之另一較佳實施例中，其可與上文所述者相同或不同，在式I化合物中，基團

， 在每次出現時彼此獨立地表示

較佳

。 在本發明之一個尤其較佳實施例中，在式I化合物中，全部基團

表示具有相同含義。 此等化合物非常適用作液晶混合物中之穩定劑。特定言之，其使混合物之VHR對UV曝露穩定。 在本發明之一個較佳實施例中，根據本發明之介質在各情況下包含選自式I-1至I-8，較佳至I-6之化合物之群，較佳選自式I-1至I-5，尤其較佳式I-2及/或I-3及/或I-4之化合物之群的一或多種式I化合物，

及

其中參數具有上文根據式I指示之含義。 除式I或其較佳子式之化合物外，根據本發明之介質較佳包含總濃度在5%或更高至90%或更低，較佳10%或更高至80%或更低，尤其較佳20%或更高至70%或更低範圍內的一或多種介電中性式II之化合物。 根據本發明之介質較佳包含選自式III-1至III-4之群的一或多種化合物，其總濃度在10%或更高至80%或更低，較佳15%或更高至70%或更低，尤其較佳20%或更高至60%或更低範圍內。 根據本發明之介質尤其較佳包含 總濃度在5%或更高至30%或更低範圍內的一或多種式III-1化合物， 總濃度在3%或更高至30%或更低範圍內的一或多種式III-2化合物， 總濃度在5%或更高至30%或更低範圍內的一或多種式III-3化合物， 總濃度在1%或更高至30%或更低範圍內的一或多種式III-4化合物。 較佳式II化合物為選自式II-1及II-2之化合物之群，較佳為式II-1之化合物，

其中 烷基 表示具有1至7個C原子，較佳具有2至5個C原子之烷基， 烯基 表示具有2至5個C原子，較佳具有2至4個C原子，尤其較佳2個C原子之烯基， 烯基' 表示具有2至5個C原子，較佳具有2至4個C原子，尤其較佳具有2至3個C原子之烯基。 在本發明之一個較佳實施例中，根據本發明之介質包含一或多種式B之化合物，較佳濃度為1至20%，尤其較佳2至15%且極佳3至9%，

其中 R^B1 及R^B2 在各情況下彼此獨立地表示具有1至7個C原子的未經取代之烷基、烷氧基、氧雜烷基或烷氧基烷基，或具有2至7個C原子的烯基或烯基氧基，較佳皆表示烷氧基，及 L^B1 及L^B2 在各情況下彼此獨立地表示F或Cl，較佳F。 根據本發明之介質較佳包含一或多種式III-1之化合物，較佳地選自式III-1-1及III-1-2之化合物之群的一或多種化合物，

其中參數具有上文在式III-1之情況下所給出之含義，且較佳 R³¹ 表示具有2至5個C原子，較佳具有3至5個C原子之烷基，及 R³² 表示具有2至5個C原子之烷基或烷氧基，較佳具有2至4個C原子之烷氧基，或具有2至4個C原子之烯基氧基。 根據本發明之介質較佳包含一或多種式III-2之化合物，較佳選自式III-2-1及III-2-2之化合物之群的一或多種化合物，

其中參數具有上文在式III-2之情況下所給出之含義，且較佳 R³¹ 表示具有2至5個C原子，較佳具有3至5個C原子之烷基，及 R³² 表示具有2至5個C原子之烷基或烷氧基，較佳具有2至4個C原子之烷氧基，或具有2至4個C原子之烯基氧基。 根據本發明之介質較佳包含一或多種式III-3之化合物，較佳選自式III-3-1及III-3-2之化合物之群的一或多種化合物，

其中參數具有上文在式III-3之情況下所給出之含義，較佳 R³¹ 表示具有2至5個C原子，較佳具有3至5個C原子之烷基，及 R³² 表示具有2至5個C原子之烷基或烷氧基，較佳具有2至4個C原子之烷氧基，或具有2至4個C原子之烯基氧基。 在一個較佳實施例中，根據本發明之介質包含選自式II-1及II-2之化合物之群的一或多種式II化合物。 在一個不同較佳實施例中，根據本發明之介質不包含式II之化合物。 根據本發明之介質較佳包含指定總濃度之以下化合物： 10-60重量%之選自式III-1至III-4化合物之群的一或多種化合物及/或 30-80重量%之一或多種式IV及/或V之化合物， 其中介質中之所有化合物之總含量為100%。 在一個尤其較佳實施例中，根據本發明之介質包含選自式OH-1至OH-6化合物之群的一或多種化合物，

此等化合物極適於使介質針對熱負荷穩定。 在本發明之另一較佳實施例中，其中根據本發明之介質尤其包含一或多種式I化合物，其中p表示2且n表示2、3或4，較佳2或3，尤其較佳3，此等介質具有極佳穩定性。 在本發明之另一較佳實施例中，根據本發明之介質在各情況下至少包含一或多種式I化合物，其中p表示1且n表示3、4、5或6，較佳4，且基團-Z¹¹ -S¹¹ -Z¹² -表示ω-雙氧基伸烷基，即-O-S¹¹ -O-，此等介質具有極佳穩定性。 本發明亦係關於含有根據本發明之液晶介質之電光顯示器或電光組件。較佳為基於IPS、FFS、VA或ECB效應，較佳基於IPS或FFS效應之電光顯示器，且尤其為藉助於主動矩陣式定址裝置來定址的顯示器。 因此，本發明同樣係關於根據本發明之液晶介質於電光顯示器或電光組件中之用途，且係關於用於製備根據本發明之液晶介質的方法，其特徵在於一或多種式I化合物與一或多種式II化合物，較佳與一或多種子式II-1之化合物，且與較佳選自式III-1至III-4及IV及/或V之化合物之群的一或多種其他化合物混合。 另外，本發明係關於一種使液晶介質穩定之方法，該液晶介質包含一或多種式II之化合物及一或多種選自式III-1至III-4之化合物之群的化合物，其特徵在於向介質添加一或多種式I化合物。 在另一較佳實施例中，介質包含一或多種式IV之化合物，

其中 R⁴¹ 表示具有1至7個C原子，較佳具有2至5個C原子之烷基，及 R⁴² 表示具有1至7個C原子之烷基或具有1至6個C原子之烷氧基，其皆較佳具有2至5個C原子。 在另一較佳實施例中，該介質包含一或多種式IV之化合物，其選自式IV-1及IV-2之化合物之群，

其中 烷基及烷基'， 彼此獨立地表示具有1至7個C原子，較佳具有2至5個C原子之烷基， 烷氧基 表示具有1至5個C原子，較佳具有2至4個C原子之烷氧基。 在另一較佳實施例中，介質包含一或多種式V之化合物，

其中 R⁵¹ 及R⁵² 彼此獨立地具有針對R²¹ 及R²² 所給出之含義之一，且較佳表示具有1至7個C原子之烷基，較佳為正烷基，尤其較佳為具有1至5個C原子之正烷基；具有1至7個C原子之烷氧基，較佳為正烷氧基，尤其較佳為具有2至5個C原子之正烷氧基；具有2至7個C原子，較佳具有2至4個C原子之烷氧基烷基、烯基或烯基氧基，較佳為烯基氧基，

較佳地

較佳地

及，若存在，

Z⁵¹ 至Z⁵³ 各自彼此獨立地表示-CH₂ -CH₂ -、-CH₂ -O-、-CH=CH-、-C≡C-、-COO-或單鍵，較佳表示-CH₂ -CH₂ -、-CH₂ -O-或單鍵，且尤其較佳表示單鍵， p及q 各自彼此獨立地表示0或1， (p + q) 較佳表示0或1。 在另一較佳實施例中，介質包含選自式V-1至V-10之化合物之群，較佳選自式V-1至V-5之化合物之群的一或多種式V之化合物，

其中參數具有上文在式V下所給出之含義，且 Y⁵ 表示H或F，且較佳 R⁵¹ 表示具有1至7個C原子之烷基或具有2至7個C原子之烯基，及 R⁵² 表示具有1至7個C原子之烷基、具有2至7個C原子之烯基或具有1至6個C原子之烷氧基，較佳為烷基或烯基，尤其較佳為烯基。 在另一較佳實施例中，該介質包含一或多種式V-1之化合物，其選自式V-1a及V-1b，較佳式V-1b之化合物之群，

其中 烷基及烷基'， 彼此獨立地表示具有1至7個C原子，較佳具有2至5個C原子之烷基， 烷氧基 表示具有1至5個C原子，較佳具有2至4個C原子之烷氧基。 在另一較佳實施例中，該介質包含一或多種式V-3之化合物，其選自式V-3a及V-3b之化合物之群，

其中 烷基及烷基'， 彼此獨立地表示具有1至7個C原子，較佳具有2至5個C原子之烷基，以及 烯基 表示具有2至7個C原子，較佳具有2至5個C原子之烯基。 在另一較佳實施例中，該介質包含一或多種式V-4之化合物，其選自式V-4a及V-4b之化合物之群，

其中 烷基及烷基'， 彼此獨立地表示具有1至7個C原子，較佳具有2至5個C原子之烷基。 在另一較佳實施例中，介質包含一或多種式III-4，較佳式III-4-a之化合物，

其中 烷基及烷基'， 彼此獨立地表示具有1至7個C原子，較佳具有2至5個C原子之烷基。 根據本發明之液晶介質可包含一或多種對掌性化合物。 本發明之尤其較佳實施例滿足以下條件中之一或多個， 其中首字母縮寫詞(縮寫)解釋於表A至C中且以表D中之實例說明。 i. 液晶介質之雙折射率為0.060或更高，尤其較佳為0.070或更高。 ii. 液晶介質之雙折射率為0.130或更低，尤其較佳為0.120或更低。 iii. 液晶介質之雙折射率在0.090或更高至0.120或更低之範圍內。 iv. 液晶介質具有值為2.0或更高，尤其較佳3.0或更高的負性介電各向異性。 v. 液晶介質具有值為5.5或更低，尤其較佳5.0或更低的負性介電各向異性。 vi. 液晶介質具有值在3.6或更高至5.2或更低範圍內的負性介電各向異性。 vii. 液晶介質包含一或多種尤其較佳之式II化合物，其選自下文給出之子式：

其中烷基具有上文給出之含義且較佳在各情況下彼此獨立地表示具有1至6個，較佳具有2至5個C原子之烷基，且尤其較佳為正烷基。 viii. 混合物中式II之化合物的總濃度整體為25%或更高，較佳為30%或更高，且較佳在25%或更高至49%或更低之範圍內，尤其較佳在29%或更高至47%或更低之範圍內，且極佳在37%或更高至44%或更低之範圍內。 ix. 液晶介質包含選自下式之化合物之群的一或多種式II之化合物：CC-n-V及/或CC-n-Vm，尤其較佳為CC-3-V，較佳濃度為至多50%或更低，尤其較佳至多42%或更低，且視情況存在之額外CC-3-V1，較佳濃度為至多15%或更低，及/或CC-4-V，較佳濃度為至多20%或更低，尤其較佳至多10%或更低。 x. 混合物中式CC-3-V之化合物之總濃度整體為20%或更高，較佳25%或更高。 xi. 混合物中式III-1至III-4之化合物的比例整體為50%或更高及較佳75%或更低。 xii. 液晶介質主要由式I、II、III-1至III-4、IV及V之化合物，較佳式I、II及III-1至III-4之化合物組成。 xiii. 液晶介質包含一或多種式IV之化合物，較佳總濃度為5%或更高，特定言之10%或更高，且極佳15%或更高至40%或更低。 本發明另外係關於一種具有基於VA或ECB效應定址之主動矩陣的電光顯示器，其特徵在於，其含有根據本發明之液晶介質作為介電質。 液晶混合物較佳具有寬度為至少80度的向列相範圍及在20℃下至多30 mm² ×s^{- 1} 的流體黏度ν₂₀ 。 根據本發明之液晶混合物具有-0.5至-8.0，特定言之-1.5至-6.0，且極佳-2.0至-5.0之Δε，其中Δε表示介電各向異性。 旋轉黏度γ₁ 較佳為150 mPa×s或更低，特定言之120 mPa×s或更低且極佳120 mPa×s或更低。 根據本發明之混合物適於全部IPS及FFS-TFT應用。其另外適於全部VA應用，諸如VAN、MVA、(S)-PVA及ASV應用，及具有負Δε之PALC應用。 根據本發明之顯示器中之向列型液晶混合物一般包含兩種組分A及B，其本身由一或多種個別化合物組成。 根據本發明之液晶介質較佳包含4至15種，特定言之5至12種，且尤其較佳10種或更少化合物。此等化合物較佳選自式I、II及III-1至III-4，及/或IV及/或V之化合物之群。 根據本發明之液晶介質亦可視情況包含超過18種化合物。在此情況中，其較佳包含18至25種化合物。 除式I至V之化合物以外，亦可存在其他組分，例如其量佔混合物整體至多45%，但較佳至多35%，特定言之至多10%。 根據本發明之介質亦可視情況包含介電正性組分，其總濃度基於整個介質較佳為10%或更低。 在一個較佳實施例中，基於混合物整體計，根據本發明之液晶介質總計包含 100 ppm或更高至2500 ppm或更低，較佳300 ppm或更高至2000 ppm或更低，尤其較佳500 ppm或更高至1500 ppm或更低且極佳700 ppm或更高至1200 ppm或更低之式I化合物， 20%或更高至60%或更低，較佳25%或更高至50%或更低，尤其較佳30%或更高至45%或更低式II之化合物，及 50%或更高至70%或更低的式III-1至III-4及/或B之化合物。 在一個較佳實施例中，根據本發明之液晶介質包含選自式I、II、III-1至III-4、IV及V之化合物之群，較佳選自式I、II及III-1至III-4及/或B之化合物之群的化合物；其較佳主要，尤其較佳基本上且極佳幾乎完全由該式之化合物組成。 根據本發明之液晶介質的向列相在各情況下較佳為至少-20℃或更低至70℃或更高，尤其較佳-30℃或更低至80℃或更高，極佳為-40℃或更低至85℃或更高且最佳為-40℃或更低至90℃或更高。 表述「具有向列相」在此意謂：一方面，在低溫在相應溫度下未觀察到近晶相及結晶，且另一方面，在加熱時在向列相外不發生清除。在低溫下之研究係在相應溫度下流量式黏度計中進行，且藉由在單元厚度對應於電光應用之測試單元中儲存至少100小時進行檢驗。若在相應測試單元中在-20℃溫度下之儲存穩定性為1000小時或更久，則認為該介質在此溫度下為穩定的。在-30℃及-40℃之溫度下，相應時間分別為500小時及250小時。在高溫下，利用習知方法在毛細管中量測清澈點。另外，在-20℃或-30℃的溫度下，在玻璃瓶中測定主體(1 mL樣品)低溫下之存放期。在此等溫度下，較佳在-30℃下，穩定存放期較佳為120小時或更久，尤其較佳240小時或更久。 在一個較佳實施例中，根據本發明之液晶介質係藉由在中等至低範圍中之光學各向異性值表徵。雙折射率值較佳在0.065或更高至0.130或更低之範圍內，尤其較佳在0.080或更高至0.120或更低之範圍內且極佳在0.085或更高至0.110或更低之範圍內。 在此實施例中，根據本發明之液晶介質具有負性介電各向異性及相對高之介電各向異性絕對值(

)，該絕對值較佳在2.7或更高至5.3或更低，較佳至4.5或更低，較佳2.9或更高至4.5或更低，尤其較佳3.0或更高至4.0或更低及極佳3.5或更高至3.9或更低範圍內。 根據本發明之液晶介質具有相對低的臨限電壓(V₀ )值，該等值在1.7 V或更高至2.5 V或更低，較佳1.8 V或更高至2.4 V或更低，尤其較佳1.9 V或更高至2.3 V或更低及極佳1.95 V或更高至2.1 V或更低範圍內。 在另一較佳實施例中，根據本發明之液晶介質較佳具有相對低的平均介電各向異性值(e_av. ≡ (e_êê + 2e_^ )/3)其較佳在5.0或更高至7.0或更低，較佳5.5或更高至6.5或更低，仍更佳5.7或更高至6.4或更低，尤其較佳5.8或更高至6.2或更低及極佳5.9或更高至6.1或更低範圍內。 另外，根據本發明之液晶介質在液晶單元中具有較高的VHR值。 在20℃下於新鮮填充之單元中，在該等單元中，此等較佳大於或等於95%，較佳大於或等於97%，尤其較佳大於或等於98%且極佳大於或等於99%，且在烘箱中在100℃下5分鐘之後，在該等單元中，此等大於或等於90%，較佳大於或等於93%，尤其較佳大於或等於96%且極佳大於或等於98%。 大體而言，具有低定址電壓或臨限電壓之液晶介質在此處具有比具有較高定址電壓或臨限電壓之該等液晶介質更低的VHR，且反之亦然。 個別物理特性之此等較佳值較佳亦在各情況下係藉由根據本發明之介質彼此組合來維持。 在本申請案中，除非另外明確指明，否則術語「化合物(compounds/compound(s)」意謂一種及複數種化合物。 除非另外指明，否則個別化合物一般用於濃度在各情況下為1%或更高至30%或更低，較佳2%或更高至30%或更低且尤其較佳3%或更高至16%或更低的混合物中。 在一個較佳實施例中，根據本發明之液晶介質包含 式I化合物， 一或多種式II之化合物，較佳選自以下之群：式CC-n-V及CC-n-Vm，較佳CC-3-V、CC-3-V1、CC-4-V及CC-5-V之化合物，尤其較佳選自以下之群：化合物CC-3-V、CC-3-V1及CC-4-V，極佳地化合物CC-3-V，及視情況另外存在之化合物CC-4-V及/或CC-3-V1， 一或多種式III-1-1，較佳式CY-n-Om之化合物，選自式CY-3-O2、CY-3-O4、CY-5-O2及CY-5-O4化合物之群， 一或多種式III-1-2之化合物，較佳選自式CCY-n-m及CCY-n-Om，較佳式CCY-n-Om之化合物之群，較佳選自式CCY-3-O2、 CCY-2-O2、CCY-3-O1、CCY-3-O3、CCY-4-O2、CCY-3-O2及CCY-5-O2之化合物之群， 視情況而言，較佳強制性地，一或多種式III-2-2，較佳式CLY-n-Om之化合物，其較佳選自式CLY-2-O4、CLY-3-O2、CLY-3-O3之化合物之群， 一或多種式III-3-2，較佳式CPY-n-Om之化合物，其較佳選自式CPY-2-O2及CPY-3-O2、CPY-4-O2及CPY-5-O2之化合物之群， 一或多種式III-4，較佳式PYP-n-m之化合物，較佳選自式PYP-2-3及PYP-2-4之化合物之群。 根據本發明的式I化合物或待根據本發明使用之式I化合物可有利地根據以下反應流程製備。 合成流程1

其中n較佳表示2、3或4，尤其較佳3或4。 在上文之反應流程中，Pg表示保護基且Rg表示離去基團且參數n具有在式I之情況中給出之含義，此外R¹ 具有針對式I之情況中的R¹¹ 給出之含義，環結構具有針對式I之情況中的ZG給出之含義，Sp¹ 及Sp² 具有在式I之情況下分別針對S¹ 及S² 給出之含義，且較佳n表示3或4，環結構表示芳族基或脂族基，Sp¹ 及Sp² 表示單鍵或具有1至8個C原子的伸烷基，且R¹ 表示具有1至8個C原子之烷基。 對於本發明，除非在個別情況下另外指明，否則結合組合物各成分之說明應用以下定義： - 「包含」：組合物中所討論之組分之濃度較佳為5%或更高，尤其較佳10%或更高，極佳為20%或更高， - 「主要由……組成」：組合物中所討論之組分之濃度較佳為50%或更高，尤其較佳為55%或更高且極佳為60%或更高， - 「基本上由……組成」：組合物中所討論之組分之濃度較佳為80%或更高，尤其較佳為90%或更高且極佳為95%或更高，及 - 「幾乎完全由……組成」：組合物中所討論之組分之濃度較佳為98%或更高，尤其較佳為99%或更高且極佳為100.0%。 此同時適用於呈具有其成分之組合物形式的介質，該等組合物可為組分及化合物，以及具有其成分之組分、化合物。僅就個別化合物相對於介質整體之濃度而言，術語包含含義：所討論之化合物之濃度較佳為1%或更高，尤佳為2%或更高，極佳為4%或更高。 對於本發明，「≤」意謂小於或等於，較佳為小於，且「≥」意謂大於或等於，較佳為大於。 對於本發明，

表示反-1,4-伸環己基，及

表示1,4-伸苯基。 對於本發明，表述「介電正性化合物」意謂Δε＞1.5之化合物，表述「介電中性化合物」意謂-1.5≤Δε≤1.5之該等化合物，且表述「介電負性化合物」意謂Δε＜-1.5之該等化合物。在此處，化合物之介電各向異性係藉由以下步驟測定：將10%化合物溶解於液晶主體中，且在各情況下測定所得混合物在至少一個測試單元中之電容，該測試單元之單元厚度為20 µm，且在1 kHz下具有垂直及均勻表面對準。量測電壓通常為0.5 V至1.0 V，但始終低於所研究之各別液晶混合物之電容臨限值。 用於介電正性及介電中性化合物的主體混合物為ZLI-4792且用於介電負性化合物之主體混合物為ZLI-2857，兩者均來自德國之Merck KGaA。待研究之各別化合物的值係自添加待研究化合物且外插至100%所用化合物之後主體混合物之介電常數的改變獲得。待研究之化合物以10%之量溶解於主體混合物中。若該物質之溶解度對於此目的過低，則在各步驟中濃度減半，直至可在所需溫度下進行該研究。 根據本發明之液晶介質在必要時亦可包含其他添加劑，諸如正常量之穩定劑及/或多色性染料及/或對掌性摻雜劑。以整個混合物之量計，所用此等添加劑之量較佳為總計0%或更高至10%或更低，尤其較佳為0.1%或更高至6%或更低。所用個別化合物之濃度較佳為0.1%或更高至3%或更低。當指定液晶介質中液晶化合物之濃度及濃度範圍時，一般不考慮此等添加劑及類似添加劑之濃度。 在一個較佳實施例中，根據本發明之液晶介質包含聚合物前驅物，其包含一或多種反應性化合物，較佳反應性液晶原基，且必要時，該等液晶介質亦進一步包含常用量之添加劑，諸如聚合引發劑及/或聚合減速劑。以整個混合物之量計，所用此等添加劑之量總計為0%或更高至10%或更低，較佳為0.1%或更高至2%或更低。當指定液晶介質中液晶化合物之濃度及濃度範圍時，不考慮該等添加劑及類似添加劑之濃度。 該等組合物由以習知方式混合的複數種化合物，較佳3種或更多至30種或更少，尤其較佳6種或更多至20種或更少，且極佳10種或更多至16種或更少化合物組成。一般而言，將以較少量使用的組分之所需量溶解於構成該混合物之主要成分的組分中。此有利地在高溫下進行。若所選溫度高於主要組分之清澈點，則特別容易觀察到溶解操作之完成。然而，亦可以其他習知方式，例如使用預混物，或由所謂的「多瓶系統(multibottle system)」製備液晶混合物。 根據本發明之混合物展現澄清點為65℃或更高之極寬向列相範圍、極有利的電容臨限值、相對較高的保持率值且同時在-30℃及-40℃下極佳之低溫穩定性。另外，根據本發明之混合物係藉由低旋轉黏度γ₁ 區分。 對於熟習此項技術者不言而喻，用於VA、IPS、FFS或PALC顯示器中的根據本發明之介質亦可包含例如H、N、O、Cl、F已經相應同位素置換之化合物。 根據本發明之液晶顯示器之結構對應於如在例如EP-A 0 240 379中所述之常見幾何結構。 藉助於適合添加劑，根據本發明之液晶相可經改質以使得其可用於迄今已揭示之任何類型(例如ECB、VAN、IPS、GH或ASM-VA LCD)顯示器中。 下表E指示可添加至根據本發明之混合物中的可能摻雜劑。若該等混合物包含一或多種摻雜劑，則其用量為0.01%至4%，較佳為0.1%至1.0%。 可例如添加至根據本發明之混合物中的較佳0.01至6%，特定言之0.1至3%之量的穩定劑顯示於下表F中。 出於本發明之目的，除非另外明確指出，否則所有濃度按重量百分比而指示，並且除非另外明確指明係關於相對應混合物或混合物組分。 除非另外明確指示，否則本申請案中所指示之所有溫度值，諸如熔點T(C,N)、近晶相(S)至向列相(N)之相變T(S,N)及清澈點T(N,I)，均以攝氏度(℃)指示，且所有溫度差異相應地均以度數差異(°或度)指示。 對於本發明，除非另外明確指示，否則術語「臨限電壓」係關於電容臨限值(V₀ )，亦稱為弗雷德里克臨限值(Freedericks threshold)。 除非在各情況下另外明確指示，否則所有物理特性均係或已根據「Merck Liquid Crystals, Physical Properties of Liquid Crystals」, status 1997年11月, Merck KGaA, Germany來測定且適用於20℃之溫度且Δn在589 nm下測定且Δε在1 kHz下測定。 電光特性，例如臨限電壓(V₀ )(電容量測值)，以及轉換行為，均係在Merck Japan製造之測試單元中測定。量測單元具有鈉鈣玻璃基板，且利用聚醯亞胺對準層(SE-1211及稀釋劑**26 (混合比1:1)，兩者均來自Nissan Chemicals, Japan)以ECB或VA組態構建，該等聚醯亞胺配向層已彼此垂直摩擦且實現液晶之垂直對準。透明、實際上正方形ITO電極之表面積為1 cm² 。 除非另外指示，否則對掌性摻雜劑並未添加至所用液晶混合物中，但後者亦特別適用於需要此類型摻雜之應用。 在日本Merck公司製造之測試單元中判定VHR。量測單元具有鈉鈣玻璃基板，且用層厚度為50 nm的聚醯亞胺對準層(例如來自日本Japan Synthetic Rubber的AL-3046，除非另外說明)或實施例中描述的對準層構造，其彼此垂直摩擦。層厚度為均勻6.0 µm。透明ITO電極之表面積為1 cm² 。 VHR在20℃(VHR₂₀ )下測定，且在100℃的烘箱中(VHR₁₀₀ )在德國Autronic Melchers的市售儀器中測定5分鐘。所用電壓之頻率為60 Hz，或實例中指定之條件。 VHR量測值之精確性取決於各別VHR值。精確性隨著減小的值而減小。一般在各種量值範圍中之值的情況下觀測到之偏差以其數量級被編輯於下表中。

對UV照射的穩定性在來自德國Heraeus的市售器具「日光測試CPS (Suntest CPS)」中研究。不使用額外加熱照射密封測試單元2.0小時。300 nm至800 nm波長範圍內的照射功率為765 W/m² V，或實例中所示的條件。具有310 nm之邊緣波長的UV「截斷」濾波器按次序使用以模擬所謂的窗玻璃模式。在每一系列實驗中，針對每一條件研究至少四個測試單元，且各別結果經指示為相對應個別量測之平均值。 通常藉由曝光(例如藉由LCD背光之UV照射)引起的電壓保持率(DVHR)的減小根據以下等式(1)來判定：

(1)。 等式(2)根據以下等式確定LC混合物相對於負載的時間t的相對穩定性(S_rel )：

(2)， 其中「ref」代表相應未穩定化之混合物。 除了VHR以外，可表徵液晶混合物之電導率的另一特徵量為離子密度。離子密度的高值通常導致發生顯示故障，例如圖像殘留及閃爍。離子密度較佳在Merck Japan Ltd.製造的測試單元中測定。測試單元具有由鈉鈣玻璃製成之基板，且設計成聚醯亞胺層厚度為40 nm的聚醯亞胺對準層(例如來自日本Japan Synthetic Rubber的AL-3046，除非另外說明)。液晶混合物之層厚度為均勻6.0 µm。另外裝配有保護環之圓形透明ITO電極之面積為1 cm² 。量測方法之精確度為約±15%。單元在120℃下在烘箱中乾燥隔夜，隨後用相關液晶混合物填充。 使用來自日本東京之市售儀器來量測離子密度。如M. Inoue, 「Recent Measurement of Liquid Crystal Material Characteristics」, Proceedings IDW 2006, LCT-7-1,647中所述，量測方法基本上為類似於循環伏安法的量測方法。在此方法中，施加之直流電壓根據預先指定的三角形輪廓在正及負最大值之間變化。藉由特徵曲線的完整操作形成一個量測週期。若施加之電壓足夠大以使場中之離子能夠移動至相應電極，則由於離子的放電而形成離子電流。此處轉移之電荷的量通常在幾pC至幾nC範圍內。此使得需要高靈敏感之偵測，其由上述儀器確保。結果以電流/電壓曲線描繪。此處之離子電流由在小於液晶混合物之臨限電壓的電壓下出現峰值而顯而易知。峰面積之積分獲得所研究之混合物的離子密度值。每種混合物量測四種測試單元。三角波電壓之重複頻率為0.033 Hz，量測溫度為60℃，最大電壓為±3 V至±10 V，取決於相關混合物之介電各向異性的量值。 旋轉黏度係使用旋轉永久磁鐵方法測定，且流動黏度在改良之烏氏黏度計(Ubbelohde viscometer)中測定。對於液晶混合物ZLI-2293、ZLI-4792及MLC-6608(所有產品均來自Merck KGaA, Darmstadt, Germany)，在20℃下測定之旋轉黏度值分別為161 mPa·s、133 mPa·s及186 mPa·s，且流體黏度值(ν)分別為21 mm² ·s^{- 1} 、14 mm² ·s^{- 1} 及27 mm² ·s^{- 1} 。 除非另外明確指示，否則使用以下符號： V₀ 臨限電壓，在20℃下之電容[V]， n_e 在20℃及589 nm下量測之異常折射率， n_o 在20℃及589 nm下量測之普通折射率， Dn 在20℃及589 nm下量測之光學各向異性， e_^ 在20℃及1 kHz下，垂直於指向矢之介電磁感率， e_÷÷ 在20℃及1 kHz下，平行於指向矢之介電磁感率， De 在20℃及1 kHz下之介電各向異性， cl.p.或 T(N,I) 澄清點[℃]， n 在20℃下量測之流動黏度[mm² ·s^{- 1} ]， g₁ 在20℃下之旋轉黏度[mPa·s]， K₁ 彈性常數，在20℃下之「傾斜」變形[pN]， K₂ 彈性常數，在20℃下之「扭轉」變形[pN]， K₃ 彈性常數，在20℃下之「彎曲」變形[pN]， LTS 在測試單元中測定之相的低溫穩定性， VHR 電壓保持率， DVHR 電壓保持率之降低， S_rel VHR的相對穩定性。 以下實例解釋本發明，而不限制本發明。然而，其向熟習此項技術者展示較佳混合物概念與較佳使用之化合物及其各別濃度及其彼此之組合。此外，實例說明可獲得的特性及特性組合。 對於本發明而言及在以下實例中，藉助於縮寫詞指示液晶化合物之結構，其中根據下表A至表C進行化學式之轉化。所有基團C_n H_2n+1 、C_m H_2m+1 及C_l H_2l+1 或C_n H_2n 、C_m H_2m 及C_l H_2l 均為直鏈烷基或伸烷基，在各情況下分別具有n、m及l個C原子。表A顯示化合物之原子核之環形元素的編碼，表B列出橋接單元，且表C列出分子之左右端基之符號的含義。首字母縮寫詞由以下構成：具有視情況存在之鍵聯基團之環元素的碼，接著第一連字符及左側端基的碼，以及第二連字符及右側端基之碼。表D展示化合物之說明性結構及其各別縮寫。表 A ：環要素

表 B ：橋接單元

表 C ： 端基

其中n及m各自為整數，且三點「...」係來自此表之其他縮寫之占位。 除式I化合物以外，根據本發明之混合物較佳包含如下所提及之化合物中之一或多種化合物。 使用以下縮寫： (n、m及z各自彼此獨立地為整數，較佳為1至6)表 D

表E展示較佳用於根據本發明之混合物中的對掌性摻雜劑。表 E

在本發明之較佳實施例中，根據本發明之介質包含選自表E之化合物之群的一或多種化合物。 表F顯示除式I化合物外，亦可較佳用於根據本發明之混合物中的穩定劑。此處參數n表示在1至12範圍內之整數。特定言之，所示酚類衍生物可因其充當抗氧化劑而用作額外穩定劑。表 F

在本發明之一個較佳實施例中，根據本發明之介質包含選自表F之化合物之群的一或多種化合物，尤其選自以下兩式之化合物之群的一或多種化合物

實例 以下實例解釋本發明而不以任何方式對其進行限制。然而，物理特性使得可實現何種特性及可在何種範圍內修改對於熟習此項技術者而言為明確的。特定言之，因此熟習此項技術者明確界定可較佳達成之多種特性之組合。物質實例 以下物質為根據本申請案之較佳式I之物質或較佳根據本申請案使用之式I之物質。

及

。 以下實例解釋本發明而不以任何方式限制本發明。然而，物理特性使得熟習此項技術者瞭解可實現何種特性及其可在何種範圍內進行修正。特定言之，因此熟習此項技術者明確界定可較佳達成之多種特性之組合。合成實例 1 ： 合成2-{3-[2,5-雙({4-丁基-5-[(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)氧基]-4-{[(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)氧基]羰基}-5-側氧基戊基})苯基]丙基}-2-丁基丙二酸雙(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)酯1 (物質實例1)

步驟1.1：合成3-[3,4-雙(3-羥丙基)苯基]丙-1-醇A

將51.34 g (484.0 mmol)無水碳酸鈉溶解於171.7 ml水中。添加25.0 g (79.0 mmol) 1,2,4-三溴苯及67.7 g (476 mmol) 2-丁氧基-1,2-氧雜硼㖦於965.2 ml四氫呋喃(THF)中之溶液，添加1.65 ml (11.9 mmol)三乙胺，且攪拌混合物及使用氬氣流脫氣30分鐘。添加1.40 g (7.49 mmol)氯化鈀(II) (59%鈀，無水)及1.85 g (3.97 mmol) 2-二環己基膦基-2',6'-二-異丙氧基-1,1'-聯苯，且在回流下攪拌反應混合物18小時。使反應混合物冷卻至室溫(RT)，添加水及甲基第三丁基醚(MTBE)，且分離各相。用MTBE萃取水相，且用飽和NaCl溶液洗滌經合併之有機相，經硫酸鈉乾燥，過濾且真空蒸發。獲得呈淡黃色油狀之產物且經具有乙酸乙酯(EA)及甲醇(9:1)之混合物的矽膠過濾。合併產物溶離份且真空蒸發，獲得呈淺黃色油狀之反應產物。產物藉助於NMR光譜表徵。¹ H NMR (500 MHz, DMSO-d6) δ = 1.66 (m_c , 6H, CH₂ ), 2.42 - 2.69 (m_{( 與 DMSO 重疊 )} , 6H, CH₂ ,), 3.36 - 3.49 (m, 6H, CH₂ ), 4.44 (t, J = 5.15 Hz, 1H), 4.48 (m_c , 2H), 6.92 (dd, J = 1.7, 7.72 Hz, 1H), 6.95 (d, J = 1.53 Hz, 1H), 7.03 (d, J = 7.7 Hz, 1 H)。 步驟1.2：合成1,2,4-參(3-碘丙基)苯B

將30.2 ml (138 mmol)三苯膦溶解於513 ml乙腈中，且在溫和冷卻下逐滴添加34.92 g (138.0 mmol)碘於513 ml乙腈中之溶液。在此添加期間形成橙色懸浮液。當添加完成時，進一步攪拌混合物10分鐘。添加13.3 g (197 mmol)咪唑，且隨後逐滴添加10.0 g (39.3 mmol)三醇A於100 ml乙腈中之溶液(在此添加期間形成透明黃色溶液)。在室溫下攪拌反應溶液3小時且小心地倒入冷硫代硫酸鈉溶液中(發生脫色)，且添加庚烷。藉由攪拌洗滌之後，分離各相，用庚烷萃取水相，且經合併之有機相用水洗滌，經硫酸鈉乾燥，過濾且真空蒸發。粗產物經具有庚烷(H)及乙酸乙酯(8:2)之矽膠過濾，且蒸發產物溶離份獲得呈無色油狀之產物。產物藉助於質譜表徵。 MS (EI) = 582.0 步驟1.3：合成2-丁基丙二醯二氯C

首先向反應設備中引入76.00 g (474.5 mmol) 2-丁基丙二酸且升溫至40℃。接著經約30分鐘之時程逐滴添加90.00 ml (1.240 mol)亞硫醯二氯(小心，氣體逸出)，且在室溫(RT)下再攪拌混合物5小時。在此時間間隔內氣體逸出顯著減少。接著在50℃下攪拌反應溶液18小時且隨後在70℃下攪拌5小時。隨著溫度升高，再次發生氣體輕微逸出。反應混合物接著冷卻至室溫且溶解於300 ml無水甲苯中，且藉由與甲苯一起蒸餾(8毫巴及室溫至80℃的最大浴槽溫度)分離出過量亞硫醯二氯，獲得呈淡褐色液體狀之粗產物，其可直接用於隨後合成步驟中。 步驟1.4：合成2-丁基丙二酸雙(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)酯D

將45.3 g (262.9 mmol) 4-羥基-2,2,6,6-四甲基哌啶1-烴氧基(自由基)及40.1 ml (289.15 mmol)三乙胺溶解於419 ml二氯甲烷(DCM)中且冷卻至-11℃。接著經1.5小時之時程在-11℃至-6℃下逐滴添加25.9 g (131.4 mmol)酸氯化物C 於252 ml DCM中之溶液。反應混合物在最高0℃下攪拌約3小時緩慢解凍且在室溫(RT)下攪拌18小時。在3-6℃下在冷卻下添加飽和NaHCO₃ 溶液，簡單攪拌混合物，且分離各相。用DCM萃取水相，且合併有機相，用飽和NaCl溶液洗滌，經硫酸鈉乾燥，過濾且真空蒸發。獲得之粗產物(橙色固體)經具有DCM/MTBE (9:1)之矽膠過濾，且真空蒸發產物溶離份，獲得呈橙色晶體狀之產物。 步驟1.5：合成2-{3-[2,5-雙({4-丁基-5-[(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)氧基]-4-{[(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)氧基]羰基}-5-側氧基戊基})苯基]丙基}-2-丁基丙二酸雙(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)酯1

將0.31 g (7.80 mmol)氫化鈉(石蠟油中60%懸浮液)懸浮於9.7 ml N,N-二甲基甲醯胺(DMF)中。在溫和冷卻下逐滴添加3.75 g (7.87 mmol)雙自由基D 溶解於29.0 ml DMF中之溶液(逸出氣體)，且在室溫下攪拌混合物1小時。1.40 g (2.39 mmol)參碘B 逐滴添加至反應溶液(經5分鐘5℃熱析出)，且在室溫下攪拌混合物3小時。將反應混合物小心地添加至氯化銨溶液且用MTBE萃取。分離各相，且水相用MTBE萃取，用飽和NaCl溶液洗滌，經硫酸鈉乾燥，過濾且真空蒸發。所獲得之橙色粗產物經具有乙酸乙酯/庚烷(1:1)之矽膠過濾，且產物溶離份真空蒸發，獲得呈橙色固體狀之產物，其以玻璃樣方式發泡。產物具有以下特性。 相：玻璃態轉變溫度(Tg)=23.5℃，自150℃分解 MS (APCI) = 1605.1 [M + H⁺ ]。合成實例 2 ： 合成2-(3-{3,5-雙[({4-丁基-5-[(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)氧基]-4-{[(1-氧基-2,2,6,6-四甲基哌啶-4-基)氧基]羰基}-5-側氧基戊基}氧基)羰基]苯甲醯氧基}丙基)-2-丁基丙二酸雙(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)酯2

步驟2.1：合成2-丁基-2-[3-(噁烷-2-基氧基)丙基]丙二酸雙(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)酯E

將3.20 g (80.4 mmol)氫化鈉(石蠟油中60%懸浮液)懸浮於30 ml DMF中。在溫和冷卻下將32.40 g (69.14 mmol)雙自由基D (來自化合物1 之合成)於300 ml DMF中之溶液逐滴添加至反應溶液(逸出氣體)，且在室溫下攪拌混合物1小時。接著在室溫下逐滴添加19.0 g (85.16 mmol) 2-(3-溴丙氧基)四氫哌喃於200 ml DMF中之溶液(0.5℃熱析出)。對於在溫度提高之前的反應混合物脫氣，藉助於浸沒之巴斯德移液管(Pasteur pipette)使平緩氬氣流穿過反應混合物持續30分鐘，且隨後在35℃下攪拌混合物18小時。使反應溶液冷卻至室溫，添加至飽和NaCl溶液且用MTBE萃取，且分離各相。用MTBE萃取水相，且合併有機相，用飽和NaCl溶液洗滌，經硫酸鈉乾燥，過濾且真空蒸發，獲得用於純化之呈紅色油狀物之粗產物，將其經具有DCM/MTBE(9:1)之矽膠過濾，獲得呈紅色油狀物之產物。 步驟2.2：合成2-丁基-2-(3-羥基丙基)丙二酸雙(1-羥基-2,2,6,6-四甲基哌啶-4-基)酯F

將36.5 g (56.1 mmol)雙自由基E 及9.50 g (55.2 mmol)甲苯-4-磺酸單水合物溶解於500 ml甲醇與50 ml水之混合物中，且在40℃下攪拌混合物5小時。反應溶液冷卻至室溫且在冷卻下使用NaHCO₃ 溶液調整至pH =9且真空蒸發。殘餘物水溶液用MTBE萃取，且經合併之有機相用飽和NaCl溶液洗滌，經硫酸鈉乾燥，過濾且真空蒸發，獲得紅色油狀物，將其溶解於250 ml DCM中，添加6.00 g (55.6 mmol) MnO₂ ，且在室溫下攪拌混合物1小時。(在移除THP保護基之情況下，在一些情況中自由基亦轉化成OH化合物，其使用MnO₂ 逆轉)。反應混合物經具有DCM之矽膠過濾前真空蒸發。獲得之粗產物經具有DCM/MTBE (7:3)之矽膠過濾，且真空蒸發產物溶離份獲得紅色油狀物。 步驟2.3：合成2-(3-{3,5-雙[({4-丁基-5-[(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)氧基]-4-{[(1-氧基-2,2,6,6-四甲基哌啶-4-基)氧基]羰基}-5-側氧基戊基}氧基)羰基]-苯甲醯氧基}丙基)-2-丁基丙二酸雙(1-烴氧基-2,2,6,6-四甲基哌啶-4-基)酯2

在室溫下將6.70 g (11.7 mmolF 及50.0 mg (0.41 mmol) 4-(二甲基胺基)吡啶溶解於100 ml二氯甲烷中，且使混合物冷卻至4℃。接著添加5.00 ml (36.1 mmol)三乙胺，且隨後在3-4℃下逐滴添加1.00 g (3.77 mmol) 1,3,5-苯三羰基氯於10 ml DCM中之溶液。當熱析出完成時，使混合物升溫至室溫且隨後在室溫下攪拌18小時。接著在冷卻下添加氯化銨溶液，簡單攪拌混合物，分離各相，且用DCM萃取水相。經合併之有機相用稀NaCl溶液(更佳相分離)洗滌，經硫酸鈉乾燥，過濾且真空蒸發，獲得呈紅色固化發泡體狀之反應產物。對於進一步純化，產物經具有DCM/MTBE (9:1至85:15)之矽膠過濾，且真空蒸發產物溶離份。獲得之反應產物為紅色固化發泡體。其具有以下特性。 相: T_g (玻璃態轉變溫度) 52℃, C (熔點) 57℃ I, 分解＞ 175℃。 MS (APCI) = 1734。 以下化合物類似於所述合成工序製備。物質 / 合成實例 3 ：

相：T_g (玻璃態轉變溫度) -3℃ I (各向同性), 分解＞ 100℃。物質 / 合成實例 4 ：

相：T_g (玻璃態轉變溫度) 5℃ I (各向同性), 分解＞ 180℃。物質 / 合成實例 5:

相：T_g (玻璃態轉變溫度) 5℃ I (各向同性), 分解＞ 170℃。物質 / 合成實例 6 ：

相：T_g (玻璃態轉變溫度) 27℃ I (各向同性)。物質 / 合成實例 7 ：

物質 / 合成實例 8 ：

相：T_g (玻璃態轉變溫度) -3℃ I (各向同性)。物質 / 合成實例 9 ：

混合物實例 製備且研究具有如在下表中指示之組成及特性之液晶混合物。藉由與作為參考(Ref.)之不穩定基劑混合物相比，顯示包含式I化合物之混合物之改良穩定性。實例 1 . 1 至 1 . 3 及相應比較實例 製備且研究以下混合物(M-1)。

注意：此處，如本申請案全文，除非另外規定，否則t.b.d.意謂待測定。 首先，測定混合物(M-1)自身之電壓保持率之穩定性。在測試單元中研究混合物M-1背光照射之穩定性，該測試單元具有針對平面對準之對準材料，6.0 μm之層厚度及平坦ITO電極。為此，對混合物進行曝露於背光之測試。為此，研究相應測試單元對用針對LCD之LED (發光二極體)背光發光之穩定性。為此，填充及密封相應測試單元。此等單元接著曝露於用針對LCD之市售LED背光之多種時間的發光(168小時、336小時、500小時以及1000小時)。除了背光產生的熱量之外，不存在額外加熱。在各情況下，在100℃溫度下5分鐘之後，測定「電壓保持率」。結果編輯於下表，表1a中。 此處，如下文，填充六個測試單元且研究每一種個別混合物。所指示之值為六個個別值之平均值。 多種量測系列中之「電壓保持率」值之相對偏差通常在約3至4%範圍內。 100 ppm參考化合物R-1至R-3

接著添加至另外三份混合物M-1中之每一者，且各情況下100 ppm三種化合物I-1至I-3中之一者

添加至混合物M-1之三個其他部分之每一者，且所得混合物(C-1.1、C-1.2及C-1.3，以及M-1.1、M-1.2及M-1.3)之穩定性如上文所述研究。結果展示於下表，表1a至1d中。 表1a

表1b

表1c

表1d

實例 2 . 1 . 1 至 2 . 6 . 3 及相應比較實例 製備及研究以下混合物(M-2)。

此混合物，混合物M-2在下文關於其電壓保持率對UV輻射照射之穩定性進行研究。為此，此混合物亦分成若干份。 首先，測定混合物(M-1)本身之穩定性。為此，在測試單元中研究混合物M-1對UV曝露之穩定性，該測試單元具有適當聚醯亞胺作為針對平面對準之對準材料，6.0 μm之層厚度及平坦ITO電極。為此，相應測試單元在日光測試中照射30分鐘。在各情況下，在100℃溫度下5分鐘之後，測定電壓保持率。除非另外詳細規定，否則此處之定址頻率(或量測頻率)為60 Hz。結果編輯於表2a中。 接著，為了比較，將100 ppm、300 ppm或600 ppm參考化合物R-2添加至混合物M-2之三個部分，且所得混合物(C-1.1、C-1.2及C-1.3.)如上文所述研究。結果編輯於下表，表2a中。 如上文所指示，接著將在各情況下100 ppm、300 ppm或600 ppm化合物I-1至I-3中之一者，及以下化合物I-4至I-6

在各情況下添加至其他三分混合物M-2之組，且如上文所述研究所得混合物(C-1.1、C-1.2及C-1.3，以及M-1.1、M-1.2及M-1.3)之穩定性。結果顯示於下表，表2a及2b中。 表2a

此處容易顯而易知，化合物I-1至I-6即使在相對低濃度亦展現明顯穩定化特性。 上文所述之研究在60℃溫度及10 Hz定址/量測頻率下重複。結果編輯於下表，表2b中。 表2b

實例 3 製備及研究以下混合物(M-3)。

如實例1及2中所述，混合物M-3亦分成若干份，且原樣及在具有用於平面對準之對準材料及平坦ITO電極的測試單元中添加多種化合物來研究其曝露於LCD背光及UV光源之穩定性。實例 4 製備及研究以下混合物(M-4)。

如實例1及2中所述，混合物M-4亦分成若干份，且原樣及在具有用於平面對準之對準材料及平坦ITO電極的測試單元中添加多種化合物來研究其曝露於LCD背光及UV光源之穩定性。實例 5 製備及研究以下混合物(M-5)。

如實例1及2中所述，混合物M-5亦分成若干份，且原樣及在具有用於平面對準之對準材料及平坦ITO電極的測試單元中添加多種化合物來研究其曝露於LCD背光及UV光源之穩定性。The present invention therefore relates to compounds of formula I, and to liquid-crystalline media having a nematic phase and a negative dielectric anisotropy, comprising a) one or more compounds of formula I, preferably in a concentration of 1 ppm to 1500 ppm, preferably preferably up to 1000 ppm, preferably up to 700 ppm, especially preferably in the range of 500 ppm, preferably in the range of 10 ppm to 400 ppm, especially preferably in the range of 20 ppm to 250 ppm,

where R¹¹ In each occurrence independently of one another H, F, straight or branched alkyl chain having 1 to 20 C atoms, one of which -CH₂ - group, or if there are multiple -CH₂ -group can be replaced by -O- or -C(=O)-, but two adjacent -CH₂ -The group cannot be replaced by -O-, and one or a plurality of -CH if present₂ -The group can be replaced by -CH=CH- or -C≡C-, and one H atom or a plurality of H atoms can be replaced by F, OR¹³ , N(R¹³ )(R¹⁴ ) or R¹⁵ , R¹¹ preferably means H or alkyl, especially preferably alkyl, particularly preferably n-alkyl and very preferably n-butyl, R¹² In each occurrence independently of each other a straight or branched alkyl chain having 1 to 20 C atoms, one of which -CH₂ - group or plural -CH₂ -group can be replaced by -O- or -C(=O)-, but two adjacent -CH₂ -group is not replaceable with -O-; contains cycloalkyl or alkylcycloalkyl units and one of the -CH₂ - group or plural -CH₂ -group can be replaced by -O- or -C(=O)-, but two adjacent -CH₂ -The group cannot be replaced by -O-, and one H atom or a plurality of H atoms can be replaced by F, OR¹³ , N(R¹³ )(R¹⁴ ) or R¹⁵ The hydrocarbon group; or an aromatic or heteroaromatic hydrocarbon group, wherein one H atom or a plurality of H atoms can be replaced by F, OR¹³ , N(R¹³ )(R¹⁴ ) or R¹⁵ , R¹² preferably represents H, unbranched alkyl or branched alkyl, especially preferably H or unbranched alkyl, R¹³ In each occurrence independently of each other a straight-chain or branched alkyl or amide group having 1 to 10 C atoms, preferably an n-alkyl group, or an aromatic hydrocarbon or carboxylic acid group having 6 to 12 C atoms , R¹⁴ In each occurrence independently of each other a straight-chain or branched alkyl or amide group having 1 to 10 C atoms, preferably an n-alkyl group, or an aromatic hydrocarbon or carboxylic acid group having 6 to 12 C atoms , preferably the restriction is that in N(R¹³ )(R¹⁴ ), depending on the presence of an acyl group, R¹⁵ In each occurrence independently of each other a straight-chain or branched alkyl group having 1 to 10 C atoms, one of which -CH₂ - group or plural -CH₂ -group can be replaced by -O- or -C(=O)-, but two adjacent -CH₂ -group is not replaceable with -O-, S¹¹ and S¹² Each occurrence independently of one another represents an alkylene group having 1 to 20 C atoms, which is branched or preferably straight, preferably 1 to 20 C atoms, preferably 1 to 10 C atoms , especially preferred -(CH having 1 to 6 C atoms₂ -)_n , one of -CH₂ - group or plural -CH if present₂ -group can be replaced by -O- or -C(=O)-, but two adjacent -CH₂ -The group cannot be replaced by -O-, and one or a plurality of -CH if present₂ -The group can be replaced by -CH=CH- or -C≡C-, and one H atom or a plurality of H atoms can be replaced by F, OR¹³ , N(R¹³ )(R¹⁴ ) or R¹⁵ , or for a single bond, X¹¹ means C, Y¹¹ to Y¹⁴ each independently of the other represents methyl or ethyl, particularly preferably all represent either methyl or ethyl, and most preferably methyl, Z¹¹ to Z¹⁴ represent -O-, -(C=O)-, -O-(C=O)-, -(C=O)-O-, -O-(C=O)- independently of each other at each occurrence O-, -(NR¹³ )-, -N-R¹³ -(C=O)- or single bond, if S¹¹ is a single bond, but Z¹¹ and Z¹² Neither means -O- at the same time, and if S¹² is a single bond, then Z¹³ and Z¹⁴ Neither means -O-, Z at the same time¹¹ Preferably -O-, Z¹³ preferably represents a single bond, p represents 1 or 2, preferably 2, o represents (3-p), and if p is 2, n represents an integer from 2 to 4, preferably 2 or 3, especially preferably 3, and m represents (4-n), and if p is 1, n represents the integer 3 to 10, preferably 4 to 8, especially preferably 4 or 6, and m represents (10-n), and

and where in the case of p = 1, -X¹¹ [-R¹¹ ]_o - may alternatively represent a single bond, and b) one or more compounds of formula II

where R^{twenty one} represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably n-alkyl, especially preferably 3, 4 or 5 C atoms , and R^{twenty two} represents unsubstituted alkenyl having 2 to 7 C atoms, preferably 2, 3 or 4 C atoms, more preferably vinyl or 1-propenyl, and especially vinyl, and/or c) selected from one or more compounds of the group of formulae III-1 to III-4, preferably formula III-2, and formula B,

where R³¹ represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably an n-alkyl group, especially preferably having 2 to 5 C atoms, R³² represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, or an unsubstituted alkyl group having 1 to 6 C atoms, preferably 2, 3 or 4 C atoms The alkoxy group, and m, n and o each independently represent 0 or 1, R^B1 and R^B2 each independently of the other represents an unsubstituted alkyl, alkoxy, oxaalkyl or alkoxyalkyl group having 1 to 7 C atoms, or an alkenyl or alkenyloxy group having 2 to 7 C atoms base, and L^B1 and L^B2 Each independently of the other represents F or Cl, preferably F. In compounds of formula I, the group N(R¹³ )(R¹⁴ ) may preferably also be an amine. The following embodiments are preferred: p is 2,

In an alternative preferred embodiment, p represents 1. In this application, these elements include their corresponding isotopes. In particular, one or more of the Hs in these compounds can be replaced with a D, and in some embodiments, this is also especially preferred. The corresponding degree of hyperdeuteration of the corresponding compounds enables, for example, the detection and identification of these compounds. In some cases this is extremely helpful, especially in the case of compounds of formula I. In the present application, alkyl especially preferably means straight-chain alkyl, especially CH₃ -, C₂ H₅ -, n-C₃ H₇ -, n-C₄ H₉ -or n-C₅ H₁₁ -, and alkenyl especially preferably represents CH₂ =CH-, E-CH₃ -CH=CH-, CH₂ =CH-CH₂ -CH₂ -,E -CH₃ -CH=CH-CH₂ -CH₂ -orE -(n -C₃ H₇ )-CH=CH-. The liquid crystal medium according to the present application preferably comprises 1 ppm to 2500 ppm in total, preferably 1 ppm to 1500 ppm, preferably 1 to 600 ppm, even better 1 to 250 ppm, preferably 200 ppm, and very good 1 ppm to 100 ppm of the compound of formula I. In a preferred embodiment of the present invention, in the compound of formula I,

-Z¹² -S¹¹ -Z¹¹ -represents -O-, -S independently of each other at each occurrence¹¹ -O-, -O-S¹¹ -O-, -(C=O)-O-S¹¹ -O-, -O-(C=O)-S¹¹ -O-, -O-(C=O)-S¹¹ -(C=O)-O-, -O-S¹¹ -(C=O)-O-, -(C=O)-O-S¹¹ -C, -(C=O)-O-S¹¹ -O-(C=O)- or -(N-R¹³ )-S¹¹ -O-, -(N-R¹³ -C(=O)-S¹¹ -(C=O)-O or single bond, preferably -O-, -S¹¹ -O-, -O-S¹¹ -O-, -(C=O)-O-S¹¹ -O-, -O-(C=O)-S¹¹ -O- or -O-S¹¹ -(C=O)-O-, and/or R¹¹ If present, represents alkyl, alkoxy or H, preferably H or alkyl, and/or R¹² Represents H, methyl, ethyl, propyl, isopropyl or 3-heptyl, or cyclohexyl. In a preferred embodiment of the present application, in the compound of formula I,

represents a group selected from the group of the formula

. In a preferred embodiment of the present application, in the compound of formula I,

represents the group of groups selected from the formula

,

or

. In a preferred embodiment of the present application, in the compound of formula I, wherein p preferably represents 1,

In another preferred embodiment of the present application, in the compound of formula I, the group

Preferably, it is selected from the group of groups of the formula

,

,

,

or

. In another preferred embodiment of the present application, wherein p is 2, which may be the same as or different from those described above, in compounds of formula I,

Preferably, it is selected from the group of groups of the formula

and

. In another preferred embodiment of the present invention, which may be the same as or different from those described above, in compounds of formula I, the group

, representing each occurrence independently of each other

better

. In a particularly preferred embodiment of the present invention, in the compound of formula I, all groups

means have the same meaning. These compounds are very useful as stabilizers in liquid crystal mixtures. In particular, it stabilizes the VHR of the mixture against UV exposure. In a preferred embodiment of the invention, the medium according to the invention comprises in each case the group of compounds selected from the group of compounds of formulae I-1 to I-8, preferably to I-6, preferably selected from the group of formulae I- 1 to I-5, especially preferably one or more compounds of the formula I of the group of compounds of the formulae I-2 and/or I-3 and/or I-4,

and

wherein the parameters have the meanings indicated above according to formula I. In addition to the compounds of formula I or its preferred subformulae, the medium according to the present invention preferably comprises a total concentration of 5% or more to 90% or less, preferably 10% or more to 80% or less, especially Preferably one or more dielectrically neutral compounds of formula II in the range of 20% or higher to 70% or lower. The medium according to the invention preferably comprises one or more compounds selected from the group of formulae III-1 to III-4 in a total concentration of 10% or more to 80% or less, preferably 15% or more to 70% or less, especially preferably 20% or more to 60% or less. The medium according to the invention especially preferably comprises one or more compounds of formula III-1 in a total concentration ranging from 5% or more to 30% or less, and a total concentration ranging from 3% or more to 30% or less One or more compounds of formula III-2 within a total concentration of 5% or more to 30% or less of one or more compounds of formula III-3, a total concentration of 1% or more to 30% or less One or more compounds of formula III-4 in the low range. Preferably the compound of formula II is selected from the group of compounds of formula II-1 and II-2, preferably the compound of formula II-1,

wherein alkyl represents an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and alkenyl represents an alkyl group having 2 to 5 C atoms, preferably 2 to 4 C atoms, particularly preferably 2 An alkenyl group having 2 to 5 C atoms, alkenyl' denotes an alkenyl group having 2 to 5 C atoms, preferably 2 to 4 C atoms, particularly preferably 2 to 3 C atoms. In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of formula B, preferably in a concentration of 1 to 20%, particularly preferably 2 to 15% and very preferably 3 to 9%,

where R^B1 and R^B2 In each case, independently of one another, unsubstituted alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 7 C atoms, or alkenyl having 2 to 7 C atoms or Alkenyloxy, preferably all represent alkoxy, and L^B1 and L^B2 In each case, independently of one another, F or Cl, preferably F, is represented. The medium according to the invention preferably comprises one or more compounds of formula III-1, preferably one or more compounds selected from the group of compounds of formula III-1-1 and III-1-2,

wherein the parameters have the meanings given above in the context of formula III-1, and preferably R³¹ represents an alkyl group having 2 to 5 C atoms, preferably 3 to 5 C atoms, and R³² represents an alkyl or alkoxy group having 2 to 5 C atoms, preferably an alkoxy group having 2 to 4 C atoms, or an alkenyloxy group having 2 to 4 C atoms. The medium according to the invention preferably comprises one or more compounds of formula III-2, preferably one or more compounds selected from the group of compounds of formula III-2-1 and III-2-2,

wherein the parameters have the meanings given above in the context of formula III-2, and preferably R³¹ represents an alkyl group having 2 to 5 C atoms, preferably 3 to 5 C atoms, and R³² represents an alkyl or alkoxy group having 2 to 5 C atoms, preferably an alkoxy group having 2 to 4 C atoms, or an alkenyloxy group having 2 to 4 C atoms. The medium according to the invention preferably comprises one or more compounds of formula III-3, preferably one or more compounds selected from the group of compounds of formula III-3-1 and III-3-2,

wherein the parameters have the meanings given above in the context of formula III-3, preferably R³¹ represents an alkyl group having 2 to 5 C atoms, preferably 3 to 5 C atoms, and R³² represents an alkyl or alkoxy group having 2 to 5 C atoms, preferably an alkoxy group having 2 to 4 C atoms, or an alkenyloxy group having 2 to 4 C atoms. In a preferred embodiment, the medium according to the present invention comprises one or more compounds of formula II selected from the group of compounds of formula II-1 and II-2. In a different preferred embodiment, the medium according to the present invention does not contain the compound of formula II. The medium according to the invention preferably comprises the following compounds in the indicated total concentration: 10-60% by weight of one or more compounds selected from the group of compounds of formulae III-1 to III-4 and/or 30-80% by weight of one or A plurality of compounds of formula IV and/or V, wherein the total content of all compounds in the medium is 100%. In a particularly preferred embodiment, the medium according to the present invention comprises one or more compounds selected from the group of compounds of formula OH-1 to OH-6,

These compounds are very suitable for stabilizing the medium against thermal loads. In another preferred embodiment of the present invention, wherein the medium according to the present invention especially comprises one or more compounds of formula I, in which p represents 2 and n represents 2, 3 or 4, preferably 2 or 3, particularly preferably 3 , these media have excellent stability. In another preferred embodiment of the invention, the medium according to the invention comprises in each case at least one or more compounds of formula I, in which p represents 1 and n represents 3, 4, 5 or 6, preferably 4, and group-Z¹¹ -S¹¹ -Z¹² - Represents ω-bisoxyalkylene, i.e. -O-S¹¹ -O-, these media have excellent stability. The invention also relates to electro-optical displays or electro-optical components comprising the liquid-crystalline medium according to the invention. Preferred are electro-optic displays based on the IPS, FFS, VA or ECB effect, preferably based on the IPS or FFS effect, and especially displays addressed by means of active matrix addressing devices. The present invention thus also relates to the use of the liquid-crystalline media according to the invention in electro-optic displays or electro-optical components, and to a process for preparing the liquid-crystalline media according to the invention, characterized in that one or more compounds of the formula I are combined with one or more Compounds of formula II, preferably in admixture with one or more compounds of sub-formula II-1, preferably in admixture with one or more other compounds selected from the group of compounds of formulae III-1 to III-4 and IV and/or V . In addition, the present invention relates to a method for stabilizing liquid-crystalline media comprising one or more compounds of the formula II and one or more compounds selected from the group of compounds of the formulae III-1 to III-4, characterized in that The medium adds one or more compounds of formula I. In another preferred embodiment, the medium comprises one or more compounds of formula IV,

where R⁴¹ represents an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and R⁴² represents an alkyl group having 1 to 7 C atoms or an alkoxy group having 1 to 6 C atoms, both of which preferably have 2 to 5 C atoms. In another preferred embodiment, the medium comprises one or more compounds of formula IV selected from the group of compounds of formula IV-1 and IV-2,

wherein alkyl and alkyl', independently of each other represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and alkoxy represents an alkyl group having 1 to 5 C atoms, preferably 2 to 5 C atoms Alkoxy of 4 C atoms. In another preferred embodiment, the medium comprises one or more compounds of formula V,

where R⁵¹ and R⁵² independently of each other have for R^{twenty one} and R^{twenty two} One of the meanings given, and preferably represents an alkyl group having 1 to 7 C atoms, preferably an n-alkyl group, especially preferably an n-alkyl group having 1 to 5 C atoms; having 1 to 7 An alkoxy group having 1 C atoms, preferably an n-alkoxy group, particularly preferably an n-alkoxy group having 2 to 5 C atoms; having 2 to 7 C atoms, preferably 2 to 4 C atoms alkoxyalkyl, alkenyl or alkenyloxy, preferably alkenyloxy,

preferably

preferably

and, if it exists,

Z⁵¹ to Z⁵³ each independently represents -CH₂ -CH₂ -, -CH₂ -O-, -CH=CH-, -C≡C-, -COO- or single bond, preferably -CH₂ -CH₂ -, -CH₂ -O- or a single bond, and particularly preferably a single bond, p and q each independently of each other represent 0 or 1, (p + q) preferably represents 0 or 1. In another preferred embodiment, the medium comprises one or more compounds of formula V selected from the group of compounds of formula V-1 to V-10, preferably selected from the group of compounds of formula V-1 to V-5 ,

where the parameters have the meanings given above under formula V, and Y⁵ means H or F, preferably R⁵¹ represents an alkyl group having 1 to 7 C atoms or an alkenyl group having 2 to 7 C atoms, and R⁵² represents an alkyl group having 1 to 7 C atoms, an alkenyl group having 2 to 7 C atoms or an alkoxy group having 1 to 6 C atoms, preferably an alkyl group or an alkenyl group, particularly preferably an alkenyl group . In another preferred embodiment, the medium comprises one or more compounds of formula V-1 selected from the group of compounds of formula V-1a and V-1b, preferably of formula V-1b,

wherein alkyl and alkyl', independently of each other represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, and alkoxy represents an alkyl group having 1 to 5 C atoms, preferably 2 to 5 C atoms Alkoxy of 4 C atoms. In another preferred embodiment, the medium comprises one or more compounds of formula V-3 selected from the group of compounds of formula V-3a and V-3b,

wherein alkyl and alkyl', independently of each other, represent alkyl groups having 1 to 7 C atoms, preferably 2 to 5 C atoms, and alkenyl groups represent 2 to 7 C atoms, preferably 2 to 5 C atoms Alkenyl of 5 C atoms. In another preferred embodiment, the medium comprises one or more compounds of formula V-4 selected from the group of compounds of formula V-4a and V-4b,

wherein alkyl and alkyl', independently of each other, represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms. In another preferred embodiment, the medium comprises one or more compounds of formula III-4, preferably of formula III-4-a,

wherein alkyl and alkyl', independently of each other, represent an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms. The liquid-crystalline media according to the invention may comprise one or more chiral compounds. Particularly preferred embodiments of the present invention satisfy one or more of the following conditions, wherein the acronyms (abbreviations) are explained in Tables A to C and illustrated by the examples in Table D. i. The birefringence of the liquid crystal medium is 0.060 or higher, particularly preferably 0.070 or higher. ii. The birefringence of the liquid crystal medium is 0.130 or lower, particularly preferably 0.120 or lower. iii. The birefringence of the liquid crystal medium is in the range of 0.090 or higher to 0.120 or lower. iv. The liquid crystal medium has a negative dielectric anisotropy of 2.0 or higher, particularly preferably 3.0 or higher. v. The liquid crystal medium has a negative dielectric anisotropy of 5.5 or less, particularly preferably 5.0 or less. vi. The liquid crystal medium has a negative dielectric anisotropy with values ranging from 3.6 or higher to 5.2 or lower. vii. The liquid-crystalline medium comprises one or more particularly preferred compounds of formula II selected from the sub-formulas given below:

Wherein alkyl has the meaning given above and preferably in each case independently of one another represents an alkyl group having 1 to 6, preferably 2 to 5, C atoms, and particularly preferably n-alkyl. viii. The total concentration of the compound of formula II in the mixture as a whole is 25% or more, preferably 30% or more, and preferably in the range of 25% or more to 49% or less, especially preferably in 29% or higher to 47% or lower, and excellently 37% or higher to 44% or lower. ix. The liquid-crystalline medium comprises one or more compounds of the formula II selected from the group of compounds of the formula: CC-nV and/or CC-n-Vm, especially preferably CC-3-V, preferably at a concentration of up to 50 % or less, especially preferably at most 42% or less, and optionally additional CC-3-V1, preferably at a concentration of at most 15% or less, and/or CC-4-V, preferably at a concentration It is at most 20% or less, especially preferably at most 10% or less. x. The total concentration of the compound of formula CC-3-V in the mixture is 20% or higher as a whole, preferably 25% or higher. xi. The proportion of the compounds of formulae III-1 to III-4 in the mixture is 50% or more and preferably 75% or less as a whole. xii. The liquid-crystalline medium consists essentially of the compounds of the formulae I, II, III-1 to III-4, IV and V, preferably the compounds of the formulae I, II and III-1 to III-4. xiii. The liquid crystal medium comprises one or more compounds of formula IV, preferably in a total concentration of 5% or higher, in particular 10% or higher, and very preferably 15% or higher to 40% or lower. The invention further relates to an electro-optical display with an active matrix addressing based on the VA or ECB effect, characterized in that it contains a liquid-crystalline medium according to the invention as dielectric. The liquid crystal mixture preferably has a nematic phase range with a width of at least 80 degrees and at most 30 mm at 20°C² ×s^{- 1} The fluid viscosity ν₂₀ . The liquid crystal mixture according to the invention has a Δε of -0.5 to -8.0, in particular -1.5 to -6.0, and very well -2.0 to -5.0, wherein Δε represents the dielectric anisotropy. Rotational viscosityγ₁ It is preferably 150 mPa×s or less, specifically 120 mPa×s or less and very preferably 120 mPa×s or less. The mixtures according to the invention are suitable for all IPS and FFS-TFT applications. It is additionally suitable for all VA applications, such as VAN, MVA, (S)-PVA and ASV applications, and PALC applications with negative Δε. Nematic liquid crystal mixtures in displays according to the invention generally comprise two components A and B, which themselves consist of one or more individual compounds. The liquid-crystalline media according to the invention preferably comprise 4 to 15, in particular 5 to 12, and particularly preferably 10 or less compounds. These compounds are preferably selected from the group of compounds of formulae I, II and III-1 to III-4, and/or IV and/or V. The liquid-crystalline media according to the invention can optionally also comprise more than 18 compounds. In this case, it preferably contains 18 to 25 compounds. In addition to the compounds of formulae I to V, other components may also be present, eg in amounts of up to 45%, but preferably up to 35%, in particular up to 10%, of the mixture as a whole. The medium according to the present invention may also optionally contain a dielectrically positive component, the total concentration of which is preferably 10% or less based on the entire medium. In a preferred embodiment, based on the mixture as a whole, the liquid-crystalline media according to the invention comprise in total 100 ppm or more to 2500 ppm or less, preferably 300 ppm or more to 2000 ppm or less, especially preferred 500 ppm or more to 1500 ppm or less and very good 700 ppm or more to 1200 ppm or less of a compound of formula I, 20% or more to 60% or less, preferably 25% or more to 1200 ppm or less 50% or less, especially preferably 30% or more to 45% or less of compounds of formula II, and 50% or more to 70% or less of formulae III-1 to III-4 and/or B the compound. In a preferred embodiment, the liquid-crystalline medium according to the invention comprises the group of compounds selected from the group consisting of compounds of formulae I, II, III-1 to III-4, IV and V, preferably selected from the group consisting of formulae I, II and III-1 A compound of the group of compounds to III-4 and/or B; it preferably consists essentially, especially preferably essentially and very preferably almost entirely, of a compound of the formula. The nematic phase of the liquid-crystalline media according to the invention is preferably in each case at least -20°C or lower to 70°C or higher, particularly preferably -30°C or lower to 80°C or higher, very preferably -40°C or lower to 85°C or higher and most preferably -40°C or lower to 90°C or higher. The expression "having a nematic phase" here means: on the one hand, no smectic phase and no crystallization are observed at the corresponding temperature at low temperatures, and on the other hand, no scavenging takes place outside the nematic phase upon heating. The studies at low temperatures were carried out in a flow viscometer at the corresponding temperature and were checked by storage in a test cell with a cell thickness corresponding to the electro-optical application for at least 100 hours. The medium is considered to be stable at this temperature if it has a storage stability of 1000 hours or more at a temperature of -20°C in the corresponding test unit. At temperatures of -30°C and -40°C, the corresponding times were 500 hours and 250 hours, respectively. At high temperature, the clear point is measured in the capillary using known methods. In addition, the shelf life of the main body (1 mL sample) at low temperature was determined in a glass vial at a temperature of -20°C or -30°C. At these temperatures, preferably at -30°C, the stable storage period is preferably 120 hours or more, particularly preferably 240 hours or more. In a preferred embodiment, the liquid crystal medium according to the invention is characterized by an optical anisotropy value in the medium to low range. The birefringence value is preferably in the range of 0.065 or higher to 0.130 or lower, particularly preferably in the range of 0.080 or higher to 0.120 or lower and most preferably in the range of 0.085 or higher to 0.110 or lower within the range. In this embodiment, the liquid-crystalline medium according to the invention has a negative dielectric anisotropy and a relatively high absolute value of the dielectric anisotropy (

), the absolute value is preferably 2.7 or higher to 5.3 or lower, preferably 4.5 or lower, preferably 2.9 or higher to 4.5 or lower, particularly preferably 3.0 or higher to 4.0 or lower and excellent 3.5 or higher to 3.9 or lower. The liquid-crystalline media according to the invention have a relatively low threshold voltage (V₀ ) values at 1.7 V or more and 2.5 V or less, preferably 1.8 V or more and 2.4 V or less, especially preferably 1.9 V or more and 2.3 V or less and very good 1.95 V or higher to 2.1 V or lower. In another preferred embodiment, the liquid crystal medium according to the present invention preferably has a relatively low average dielectric anisotropy value (e_av. ≡ (e_êê + 2e_^ )/3) It is preferably 5.0 or higher to 7.0 or lower, preferably 5.5 or higher to 6.5 or lower, still more preferably 5.7 or higher to 6.4 or lower, especially preferably 5.8 or higher To 6.2 or lower and very good 5.9 or higher to 6.1 or lower. In addition, the liquid crystal media according to the invention have higher VHR values in liquid crystal cells. In freshly filled cells at 20°C these are preferably greater than or equal to 95%, preferably greater than or equal to 97%, especially preferably greater than or equal to 98% and very preferably greater than or equal to 99 %, and after 5 minutes in an oven at 100°C, in these units, these are greater than or equal to 90%, preferably greater than or equal to 93%, especially preferably greater than or equal to 96% and very good greater than or equal to 98%. In general, liquid crystal media with a low addressing voltage or threshold voltage here have a lower VHR than those with a higher addressing voltage or threshold voltage, and vice versa. These preferred values of the individual physical properties are preferably also maintained in each case by the combination of the media according to the invention with each other. In this application, unless expressly indicated otherwise, the term "compounds/compound(s)" means one or more compounds. Unless otherwise indicated, individual compounds are generally used in concentrations of in each case 1% or Up to 30% or lower, preferably 2% or higher up to 30% or lower and especially preferably 3% or higher up to 16% or lower in a mixture. In a preferred embodiment, according to The liquid crystal medium of the present invention comprises a compound of formula I, one or more compounds of formula II, preferably selected from the following group: formula CC-nV and CC-n-Vm, preferably CC-3-V, CC-3-V1 , CC-4-V and CC-5-V compounds, especially preferably selected from the following group: compounds CC-3-V, CC-3-V1 and CC-4-V, very preferably compound CC-3 -V, and optionally additional compounds CC-4-V and/or CC-3-V1, one or more compounds of formula III-1-1, preferably of formula CY-n-Om, selected from the group consisting of formula CY- Group of 3-O2, CY-3-O4, CY-5-O2 and CY-5-O4 compounds, one or more compounds of formula III-1-2, preferably selected from formula CCY-nm and CCY-n- Om, preferably a group of compounds of formula CCY-n-Om, preferably selected from the group of formula CCY-3-O2, CCY-2-O2, CCY-3-O1, CCY-3-O3, CCY-4-O2, The group of compounds of CCY-3-O2 and CCY-5-O2, as the case may be, preferably mandatory, one or more compounds of formula III-2-2, preferably of formula CLY-n-Om, which are more Preferably selected from the group of compounds of formula CLY-2-O4, CLY-3-O2, CLY-3-O3, one or more compounds of formula III-3-2, preferably of formula CPY-n-Om, preferably Selected from the group of compounds of formula CPY-2-O2 and CPY-3-O2, CPY-4-O2 and CPY-5-O2, one or more compounds of formula III-4, preferably of formula PYP-nm, preferably Selected from the group of compounds of formula PYP-2-3 and PYP-2-4. Compounds of formula I according to the invention or compounds of formula I to be used according to the invention can advantageously be prepared according to the following reaction schemes. Synthetic Scheme 1

wherein n preferably represents 2, 3 or 4, particularly preferably 3 or 4. In the reaction scheme above, Pg represents a protecting group and Rg represents a leaving group and the parameter n has the meaning given in the case of formula I, and furthermore R¹ with R in the case of formula I¹¹ The meaning given, the ring structure has the meaning given for ZG in the case of formula I, Sp¹ and Sp² With in the case of formula I, respectively for S¹ and S² The meanings given, and preferably n represents 3 or 4, the ring structure represents an aromatic or aliphatic group, Sp¹ and Sp² represents a single bond or an alkylene group having 1 to 8 C atoms, and R¹ Represents an alkyl group having 1 to 8 C atoms. For the present invention, unless otherwise indicated in individual cases, the following definitions apply in conjunction with the description of the ingredients of the composition: - "comprising": the concentration of the components in question in the composition is preferably 5% or higher, especially preferably 10% or more, very preferably 20% or more, - "consisting essentially of": the concentration of the components in question in the composition is preferably 50% or more, especially preferably 55% or more and most preferably 60% or more, - "consisting essentially of": the concentration of the components in question in the composition is preferably 80% or more, especially preferably 90% or more High and excellently 95% or more, and - "consisting almost entirely of": the concentration of the components in question in the composition is preferably 98% or more, especially preferably 99% or more And the best is 100.0%. This also applies to media in the form of compositions with their components, which may be components and compounds, as well as components, compounds with their components. With regard to the concentration of the individual compounds relative to the medium as a whole, the terms contain meanings: the concentration of the compound in question is preferably 1% or more, more preferably 2% or more, very preferably 4% or more. For the purposes of the present invention, "≤" means less than or equal to, preferably less than, and "≥" means greater than or equal to, preferably greater than. For the present invention,

represents trans-1,4-cyclohexylene, and

Represents 1,4-phenylene. For the purposes of the present invention, the expression "dielectrically positive compound" means a compound with Δε>1.5, the expression "dielectrically neutral compound" means such compound with -1.5≤Δε≤1.5, and the expression "dielectrically negative compound" These compounds are meant to be Δε<-1.5. Here, the dielectric anisotropy of a compound is determined by dissolving 10% of the compound in a liquid crystal host and in each case determining the capacitance of the resulting mixture in at least one test cell, the cell of which 20 µm thick with vertical and uniform surface alignment at 1 kHz. The measurement voltage is typically 0.5 V to 1.0 V, but is always below the capacitance threshold for the individual liquid crystal mixtures studied. The host mixture for the dielectrically positive and dielectrically neutral compounds was ZLI-4792 and the host mixture for the dielectrically negative compounds was ZLI-2857, both from Merck KGaA, Germany. The values for the individual compounds under investigation are obtained from the change in the dielectric constant of the host mixture after addition of the compounds under investigation and extrapolation to 100% of the compounds used. The compound to be investigated was dissolved in the host mixture in an amount of 10%. If the solubility of the substance was too low for this purpose, the concentration was halved in each step until the study could be carried out at the desired temperature. The liquid-crystalline media according to the invention may optionally also contain other additives, such as normal amounts of stabilizers and/or pleochroic dyes and/or chiral dopants. The amount of these additives used is preferably a total of 0% or more to 10% or less, particularly preferably 0.1% or more to 6% or less, based on the amount of the entire mixture. The concentration of the individual compounds used is preferably 0.1% or more to 3% or less. The concentrations of these and similar additives are generally not taken into account when specifying concentrations and concentration ranges of liquid crystal compounds in liquid crystal media. In a preferred embodiment, the liquid crystal media according to the present invention comprise polymer precursors comprising one or more reactive compounds, preferably reactive mesogen groups, and if necessary, the liquid crystal media also further comprise customary amounts additives, such as polymerization initiators and/or polymerization moderators. The amount of these additives used totals 0% or more to 10% or less, preferably 0.1% or more to 2% or less, based on the amount of the entire mixture. The concentrations of these and similar additives are not taken into account when specifying the concentrations and concentration ranges of the liquid crystal compounds in the liquid crystal medium. Such compositions consist of a plurality of compounds, preferably 3 or more to 30 or less, especially preferably 6 or more to 20 or less, and very preferably 10 or less, mixed in a conventional manner More to 16 or less compounds. In general, the desired amounts of the components used in minor amounts are dissolved in the components making up the major components of the mixture. This is advantageously carried out at high temperature. Completion of the dissolution operation is particularly easily observed if the temperature is chosen above the clear point of the major components. However, the liquid crystal mixture can also be prepared in other known ways, for example using a premix, or by a so-called "multibottle system". The mixtures according to the invention exhibit a very broad nematic phase range with a clearing point of 65°C or higher, very favorable capacitance thresholds, relatively high retention values and are excellent at both -30°C and -40°C low temperature stability. In addition, the mixture according to the invention is achieved by the low rotational viscosity γ₁ distinguish. It is self-evident to those skilled in the art that the media according to the invention for use in VA, IPS, FFS or PALC displays can also contain compounds, for example H, N, O, Cl, F which have been replaced by the corresponding isotopes. The structure of the liquid crystal display according to the invention corresponds to the usual geometries as described, for example, in EP-A 0 240 379. With the aid of suitable additives, the liquid crystal phase according to the present invention can be modified so that it can be used in any type of displays disclosed so far (eg ECB, VAN, IPS, GH or ASM-VA LCD). Table E below indicates possible dopants that can be added to the mixtures according to the invention. If the mixtures contain one or more dopants, they are used in an amount of 0.01% to 4%, preferably 0.1% to 1.0%. Stabilizers, which may for example be added to the mixtures according to the invention in amounts of preferably 0.01 to 6%, in particular 0.1 to 3%, are shown in Table F below. For the purposes of the present invention, all concentrations are indicated in weight percent unless expressly indicated otherwise, and relate to the corresponding mixture or mixture components unless expressly indicated otherwise. Unless explicitly indicated otherwise, all temperature values indicated in this application, such as melting point T(C,N), smectic (S) to nematic (N) phase transition T(S,N) and clear Points T(N,I), are indicated in degrees Celsius (°C), and all temperature differences are accordingly indicated in degrees difference (° or degrees). For purposes of the present invention, unless expressly indicated otherwise, the term "threshold voltage" refers to capacitance thresholds (V₀ ), also known as the Freedericks threshold. Unless expressly indicated otherwise in each case, all physical properties are or have been determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", status November 1997, Merck KGaA, Germany and are applicable to a temperature of 20°C and Δn was measured at 589 nm and Δε was measured at 1 kHz. Electro-optic properties such as threshold voltage (V₀ ) (capacitance measurement), as well as the switching behavior, were measured in a test cell manufactured by Merck Japan. The measurement unit has a soda lime glass substrate and utilizes a polyimide alignment layer (SE-1211 and diluent**26 (mixing ratio 1:1), both from Nissan Chemicals, Japan) in ECB or VA groups Constructed in a state, the polyimide alignment layers have been rubbed perpendicular to each other and the vertical alignment of the liquid crystal is achieved. Transparent, practically square ITO electrodes with a surface area of 1 cm² . Unless otherwise indicated, parachiral dopants are not added to the liquid crystal mixtures used, but the latter are also particularly suitable for applications requiring this type of doping. The VHR was determined in a test unit manufactured by Merck, Japan. The measuring cell has a soda lime glass substrate and is constructed with a polyimide alignment layer with a layer thickness of 50 nm (eg AL-3046 from Japan Synthetic Rubber, unless otherwise stated) or an alignment layer as described in the examples , which rub perpendicularly to each other. The layer thickness is uniform 6.0 µm. The surface area of the transparent ITO electrode is 1 cm² . VHR at 20°C (VHR₂₀ ), and in an oven at 100 °C (VHR₁₀₀ ) in a commercial instrument from Autronic Melchers, Germany for 5 minutes. The frequency of the voltage used is 60 Hz, or the conditions specified in the examples. The accuracy of VHR measurements depends on the individual VHR value. Accuracy decreases with decreasing value. Deviations generally observed with values in various ranges of magnitudes are compiled in the table below by their orders of magnitude.

The stability to UV irradiation was investigated in a commercial instrument "Suntest CPS" from Heraeus, Germany. The sealed test cell was irradiated without additional heat for 2.0 hours. Irradiation power of 765 W/m in the wavelength range from 300 nm to 800 nm² V, or the condition shown in the example. UV "cut-off" filters with an edge wavelength of 310 nm were used in sequence to simulate the so-called window glass mode. In each series of experiments, at least four test units were studied for each condition, and individual results are indicated as the average of the corresponding individual measurements. The reduction in voltage holding ratio (DVHR) usually caused by exposure (eg, UV irradiation by an LCD backlight) is determined according to the following equation (1):

(1). Equation (2) determines the relative stability of the LC mixture with respect to the load time t (S_rel ):

(2), where "ref" represents the corresponding unstabilized mixture. Besides VHR, another characteristic quantity that can characterize the conductivity of liquid crystal mixtures is ion density. High values of ion density often lead to display failures such as image sticking and flickering. The ion density is preferably measured in a test cell manufactured by Merck Japan Ltd. The test cell has a substrate made of soda lime glass and is designed as a polyimide alignment layer with a polyimide layer thickness of 40 nm (eg AL-3046 from Japan Synthetic Rubber, unless otherwise stated). The layer thickness of the liquid crystal mixture was uniformly 6.0 µm. In addition, the area of the circular transparent ITO electrode equipped with the guard ring is 1 cm² . The accuracy of the measurement method is about ±15%. The cells were dried in an oven at 120°C overnight and then filled with the relevant liquid crystal mixture. The ion density was measured using a commercially available instrument from Tokyo, Japan. As described in M. Inoue, "Recent Measurement of Liquid Crystal Material Characteristics", Proceedings IDW 2006, LCT-7-1,647, the measurement method is basically a measurement method similar to cyclic voltammetry. In this method, the applied DC voltage varies between positive and negative maximum values according to a pre-specified triangular profile. A measurement cycle is formed by the complete operation of the characteristic curve. If the applied voltage is large enough to enable the ions in the field to move to the corresponding electrodes, an ionic current is formed due to the discharge of the ions. The amount of charge transferred here is usually in the range of a few pC to a few nC. This necessitates highly sensitive detection, which is ensured by the above-mentioned apparatus. Results are plotted as current/voltage curves. The ionic current here is evident from the peak at a voltage less than the threshold voltage of the liquid crystal mixture. Integration of the peak areas yields ion density values for the mixture under study. Four test units were measured for each mixture. The repetition rate of the triangular wave voltage is 0.033 Hz, the measurement temperature is 60°C, and the maximum voltage is ±3 V to ±10 V, depending on the magnitude of the dielectric anisotropy of the relevant mixture. The rotational viscosity was measured using the rotating permanent magnet method, and the flow viscosity was measured in a modified Ubbelohde viscometer. For liquid crystal mixtures ZLI-2293, ZLI-4792 and MLC-6608 (all products from Merck KGaA, Darmstadt, Germany), the rotational viscosity values measured at 20°C were 161 mPa·s, 133 mPa·s and 186 mPa, respectively s, and the fluid viscosity value (ν) is 21 mm, respectively² ·s^{- 1} , 14 mm² ·s^{- 1} and 27 mm² ·s^{- 1} . Unless explicitly indicated otherwise, the following symbols are used: V₀ Threshold Voltage, Capacitance at 20°C [V], n_e Anomalous refractive index measured at 20°C and 589 nm, n_o Ordinary refractive index measured at 20°C and 589 nm, Dn Optical anisotropy measured at 20°C and 589 nm, e_^ At 20°C and 1 kHz, the dielectric susceptibility perpendicular to the director, e_÷÷ Dielectric susceptibility parallel to the director at 20°C and 1 kHz, De dielectric anisotropy at 20°C and 1 kHz, cl.p. or T(N,I) clearing point [°C], n Flow viscosity measured at 20°C [mm² ·s^{- 1} ], g₁ Rotational viscosity at 20°C [mPa·s], K₁ Elastic constant, "tilted" deformation at 20°C [pN], K₂ Elastic constant, "torsional" deformation at 20°C [pN], K₃ Elastic constant, "bending" deformation at 20°C [pN], LTS low temperature stability of the phase measured in the test cell, VHR voltage retention, DVHR reduction in voltage retention, S_rel Relative stability of VHR. The following examples illustrate the invention without limiting it. However, it demonstrates to those skilled in the art the concept of preferred mixtures and the preferred compounds used and their respective concentrations and their combinations with each other. Furthermore, examples illustrate the properties and combinations of properties that can be obtained. For the purposes of the present invention and in the following examples, the structures of the liquid crystal compounds are indicated by means of abbreviations, wherein the transformations of the formulae are carried out according to Tables A to C below. all groups C_n H_2n+1 , C_m H_2m+1 and C_l H_2l+1 or C_n H_2n , C_m H_2m and C_l H_2l Both are straight-chain or alkylene groups, in each case having n, m and 1 C atoms, respectively. Table A shows the coding of the ring elements of the nucleus of the compound, Table B lists the bridging units, and Table C lists the meanings of the symbols for the left and right end groups of the molecules. The acronym consists of the code for the ring element with the optional linking group, followed by the code for the first hyphen and the left end group, and the second hyphen and the code for the right end group. Table D shows illustrative structures of the compounds and their respective abbreviations.surface A : Ring element

surface B : Bridge unit

surface C : end group

where n and m are each an integer, and the three dots "..." are placeholders from other abbreviations in this table. In addition to the compounds of formula I, the mixtures according to the invention preferably comprise one or more of the compounds mentioned below. The following abbreviations are used: (n, m and z are each independently an integer, preferably 1 to 6)surface D

Table E shows the chiral dopants that are preferred for use in mixtures according to the present invention.surface E

In a preferred embodiment of the present invention, the medium according to the present invention comprises one or more compounds selected from the group of compounds of Table E. Table F shows, in addition to the compounds of formula I, stabilizers which can also be preferably used in the mixtures according to the invention. The parameter n here represents an integer in the range of 1 to 12. In particular, the phenolic derivatives shown can be used as additional stabilizers as they act as antioxidants.surface F

In a preferred embodiment of the present invention, the medium according to the present invention comprises one or more compounds selected from the group of compounds of Table F, especially one or more compounds selected from the group of compounds of the following two formulae

example The following examples illustrate the invention without limiting it in any way. However, the physical properties make it clear to those skilled in the art what properties can be achieved and to what extent modifications can be made. In particular, therefore, those skilled in the art clearly define the combination of various properties that can be better achieved.Substance instance The following substances are preferred according to this application of formula I or preferably used according to this application of formula I.

and

. The following examples illustrate the invention without limiting it in any way. However, the physical properties allow those skilled in the art to understand what properties can be achieved and to what extent they can be modified. In particular, therefore, those skilled in the art clearly define the combination of various properties that can be better achieved.Synthesis example 1 : Synthesis of 2-{3-[2,5-bis({4-butyl-5-[(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)oxy] -4-{[(1-Hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)oxy]carbonyl}-5-oxypentyl})phenyl]propyl }-2-Butylmalonate bis(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)ester1 (Substance Example 1)

Step 1.1: Synthesis of 3-[3,4-bis(3-hydroxypropyl)phenyl]propan-1-olA

51.34 g (484.0 mmol) of anhydrous sodium carbonate were dissolved in 171.7 ml of water. A solution of 25.0 g (79.0 mmol) 1,2,4-tribromobenzene and 67.7 g (476 mmol) 2-butoxy-1,2-oxaborol in 965.2 ml tetrahydrofuran (THF) was added, 1.65 g ml (11.9 mmol) triethylamine, and the mixture was stirred and degassed using a stream of argon for 30 minutes. Add 1.40 g (7.49 mmol) of palladium(II) chloride (59% palladium, anhydrous) and 1.85 g (3.97 mmol) of 2-dicyclohexylphosphino-2',6'-di-isopropoxy-1, 1'-biphenyl, and the reaction mixture was stirred at reflux for 18 hours. The reaction mixture was cooled to room temperature (RT), water and methyl tert-butyl ether (MTBE) were added, and the phases were separated. The aqueous phase was extracted with MTBE and the combined organic phases were washed with saturated NaCl solution, dried over sodium sulfate, filtered and evaporated in vacuo. The product was obtained as a pale yellow oil and filtered through silica gel with a mixture of ethyl acetate (EA) and methanol (9:1). The product fractions were combined and evaporated in vacuo to give the reaction product as a pale yellow oil. The product was characterized by means of NMR spectroscopy.¹ H NMR (500 MHz, DMSO-d6) δ = 1.66 (m_c , 6H, CH₂ ), 2.42 - 2.69 (m_{( and DMSO overlapping )} , 6H, CH₂ ,), 3.36 - 3.49 (m, 6H, CH₂ ), 4.44 (t, J = 5.15 Hz, 1H), 4.48 (m_c , 2H), 6.92 (dd, J = 1.7, 7.72 Hz, 1H), 6.95 (d, J = 1.53 Hz, 1H), 7.03 (d, J = 7.7 Hz, 1H). Step 1.2: Synthesis of 1,2,4-para(3-iodopropyl)benzeneB

30.2 ml (138 mmol) of triphenylphosphine were dissolved in 513 ml of acetonitrile and a solution of 34.92 g (138.0 mmol) of iodine in 513 ml of acetonitrile was added dropwise with gentle cooling. An orange suspension formed during this addition. When the addition was complete, the mixture was stirred for a further 10 minutes. 13.3 g (197 mmol) of imidazole were added, and then a solution of 10.0 g (39.3 mmol) of Triol A in 100 ml of acetonitrile was added dropwise (a clear yellow solution formed during this addition). The reaction solution was stirred at room temperature for 3 hours and poured carefully into cold sodium thiosulfate solution (decolorization occurred), and heptane was added. After washing by stirring, the phases were separated, the aqueous phase was extracted with heptane, and the combined organic phases were washed with water, dried over sodium sulfate, filtered and evaporated in vacuo. The crude product was filtered through silica gel with heptane (H) and ethyl acetate (8:2), and the product fractions were evaporated to give the product as a colorless oil. The product was characterized by means of mass spectrometry. MS (EI) = 582.0 Step 1.3: Synthesis of 2-Butylpropanediamide dichlorideC

First, 76.00 g (474.5 mmol) of 2-butylmalonic acid were introduced into the reaction apparatus and the temperature was raised to 40°C. Then 90.00 ml (1.240 mol) of sulfite dichloride were added dropwise over the course of about 30 minutes (careful, gas evolution), and the mixture was stirred at room temperature (RT) for a further 5 hours. Gas escape was significantly reduced during this time interval. The reaction solution was then stirred at 50°C for 18 hours and then at 70°C for 5 hours. As the temperature increases, a slight escape of gas occurs again. The reaction mixture was then cooled to room temperature and dissolved in 300 ml of anhydrous toluene, and the excess thionite dichloride was isolated by co-distillation with toluene (8 mbar and maximum bath temperature from room temperature to 80° C.) to give a pale The crude product was a brown liquid, which was used directly in the subsequent synthesis step. Step 1.4: Synthesis of 2-butylmalonate bis(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)esterD

45.3 g (262.9 mmol) 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-alkoxy (radical) and 40.1 ml (289.15 mmol) triethylamine were dissolved in 419 ml dichloromethane (DCM) and cooled to -11 °C. Then 25.9 g (131.4 mmol) of acid chloride were added dropwise at -11°C to -6°C over a period of 1.5 hoursC Solution in 252 ml DCM. The reaction mixture was slowly thawed with stirring at up to 0°C for about 3 hours and stirred at room temperature (RT) for 18 hours. Add saturated NaHCO with cooling at 3-6 °C₃ solution, the mixture was briefly stirred, and the phases were separated. The aqueous phase was extracted with DCM and the organic phases were combined, washed with saturated NaCl solution, dried over sodium sulfate, filtered and evaporated in vacuo. The crude product obtained (orange solid) was filtered through silica gel with DCM/MTBE (9:1) and the product fractions were evaporated in vacuo to obtain the product as orange crystals. Step 1.5: Synthesis of 2-{3-[2,5-bis({4-butyl-5-[(1-hydrocarbyloxy-2,2,6,6-tetramethylpiperidin-4-yl) Oxy]-4-{[(1-Hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)oxy]carbonyl}-5-side oxypentyl})phenyl ]propyl}-2-butylmalonate bis(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)ester1

0.31 g (7.80 mmol) of sodium hydride (60% suspension in paraffin oil) were suspended in 9.7 ml of N,N-dimethylformamide (DMF). 3.75 g (7.87 mmol) of diradicals were added dropwise with gentle coolingD A solution in 29.0 ml DMF (evolution of gas) and the mixture was stirred at room temperature for 1 hour. 1.40 g (2.39 mmol) ginseng iodineB It was added dropwise to the reaction solution (hot precipitation at 5°C over 5 minutes), and the mixture was stirred at room temperature for 3 hours. The reaction mixture was carefully added to ammonium chloride solution and extracted with MTBE. The phases were separated and the aqueous phase was extracted with MTBE, washed with saturated NaCl solution, dried over sodium sulfate, filtered and evaporated in vacuo. The orange crude product obtained was filtered through silica gel with ethyl acetate/heptane (1:1) and the product fractions were evaporated in vacuo to give the product as an orange solid which foamed in a glassy manner. The product has the following properties. Phase: glass transition temperature (Tg) = 23.5 °C, decomposition from 150 °C MS (APCI) = 1605.1 [M + H⁺ ].Synthetic example 2 : Synthesis of 2-(3-{3,5-bis[({4-butyl-5-[(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)oxy ]-4-{[(1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl)oxy]carbonyl}-5-oxypentyl}oxy)carbonyl]benzene Methoxy}propyl)-2-butylmalonate bis(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)ester2

Step 2.1: Synthesis of 2-Butyl-2-[3-(oxan-2-yloxy)propyl]malonic acid bis(1-alkoxy-2,2,6,6-tetramethylpiperidine pyridin-4-yl)esterE

3.20 g (80.4 mmol) of sodium hydride (60% suspension in paraffin oil) were suspended in 30 ml of DMF. Under gentle cooling, 32.40 g (69.14 mmol) of diradicalD (from compound1 A solution of (Synthesis) in 300 ml DMF was added dropwise to the reaction solution (evolution of gas), and the mixture was stirred at room temperature for 1 hour. A solution of 19.0 g (85.16 mmol) of 2-(3-bromopropoxy)tetrahydropyran in 200 ml of DMF was then added dropwise at room temperature (thermal precipitation at 0.5°C). For degassing the reaction mixture prior to temperature increase, a gentle flow of argon was passed through the reaction mixture by means of a submerged Pasteur pipette for 30 minutes, and then the mixture was stirred at 35° C. for 18 hours. The reaction solution was cooled to room temperature, added to saturated NaCl solution and extracted with MTBE, and the phases were separated. The aqueous phase was extracted with MTBE, and the organic phases were combined, washed with saturated NaCl solution, dried over sodium sulfate, filtered and evaporated in vacuo to give the crude product as a red oil for purification, which was washed with DCM/MTBE (9 :1) silica gel filtration to obtain a red oily product. Step 2.2: Synthesis of 2-butyl-2-(3-hydroxypropyl)malonate bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)esterF

36.5 g (56.1 mmol) of diradicalsE and 9.50 g (55.2 mmol) of toluene-4-sulfonic acid monohydrate were dissolved in a mixture of 500 ml of methanol and 50 ml of water, and the mixture was stirred at 40° C. for 5 hours. The reaction solution was cooled to room temperature and NaHCO was used under cooling₃ The solution was adjusted to pH=9 and evaporated in vacuo. The aqueous residue solution was extracted with MTBE and the combined organic phases were washed with saturated NaCl solution, dried over sodium sulfate, filtered and evaporated in vacuo to give a red oil which was dissolved in 250 ml DCM, 6.00 g (55.6 mmol) were added ) MnO₂ , and the mixture was stirred at room temperature for 1 hour. (With removal of the THP protecting group, in some cases the radical is also converted to an OH compound, which uses MnO₂ reverse). The reaction mixture was evaporated in vacuo before being filtered through silica gel with DCM. The crude product obtained was filtered through silica gel with DCM/MTBE (7:3) and the product fractions were evaporated in vacuo to give a red oil. Step 2.3: Synthesis of 2-(3-{3,5-bis[({4-butyl-5-[(1-hydrocarbyloxy-2,2,6,6-tetramethylpiperidin-4-yl )oxy]-4-{[(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl)oxy]carbonyl}-5-side oxypentyl}oxy) Carbonyl]-benzyloxy}propyl)-2-butylmalonate bis(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)ester2

At room temperature, 6.70 g (11.7 mmolF and 50.0 mg (0.41 mmol) of 4-(dimethylamino)pyridine were dissolved in 100 ml of dichloromethane, and the mixture was cooled to 4°C. Then 5.00 ml (36.1 mmol) triethylamine were added, and then a solution of 1.00 g (3.77 mmol) 1,3,5-benzenetricarbonyl chloride in 10 ml DCM was added dropwise at 3-4°C. When thermal precipitation was complete, the mixture was allowed to warm to room temperature and then stirred at room temperature for 18 hours. Ammonium chloride solution was then added with cooling, the mixture was briefly stirred, the phases were separated and the aqueous phase was extracted with DCM. The combined organic phases are washed with dilute NaCl solution (preferably phase separated), dried over sodium sulfate, filtered and evaporated in vacuo to give the reaction product as a red solidified foam. For further purification, the product was filtered through silica gel with DCM/MTBE (9:1 to 85:15), and the product fractions were evaporated in vacuo. The obtained reaction product was a red cured foam. It has the following properties. Phase: T_g (glass transition temperature) 52°C, C (melting point) 57°C I, decomposition > 175°C. MS(APCI) = 1734. The following compounds were prepared analogously to the synthetic procedures described.substance / Synthetic example 3 :

Phase: T_g (glass transition temperature) -3°C I (isotropic), decomposition > 100°C.substance / Synthetic example 4 :

Phase: T_g (glass transition temperature) 5°C I (isotropic), decomposition > 180°C.substance / Synthetic example 5:

Phase: T_g (glass transition temperature) 5°C I (isotropic), decomposition > 170°C.substance / Synthesis example 6 :

Phase: T_g (glass transition temperature) 27°C I (isotropic).substance / Synthetic example 7 :

substance / Synthetic example 8 :

Phase: T_g (glass transition temperature) -3°C I (isotropic).substance / Synthetic example 9 :

Example of a mixture Liquid crystal mixtures with compositions and properties as indicated in the table below were prepared and investigated. The improved stability of the mixture comprising the compound of formula I is shown by comparison with the unstable base mixture as reference (Ref.).Example 1 . 1 to 1 . 3 and corresponding comparative examples The following mixture (M-1) was prepared and studied.

Note: Here, as throughout this application, unless otherwise specified, t.b.d. means to be determined. First, the stability of the voltage holding ratio of the mixture (M-1) itself was measured. The stability of mixture M-1 backlighting was investigated in a test cell with alignment material for planar alignment, a layer thickness of 6.0 μm and flat ITO electrodes. For this purpose, the mixture was tested exposed to a backlight. For this purpose, the stability of the respective test cells against light emission with an LED (Light Emitting Diode) backlight for LCDs was investigated. For this purpose, the corresponding test cells are filled and sealed. The cells were then exposed to light for various times (168 hours, 336 hours, 500 hours, and 1000 hours) with commercial LED backlights for LCDs. Apart from the heat generated by the backlight, there is no additional heating. In each case, the "voltage holding ratio" was measured after 5 minutes at a temperature of 100°C. The results are compiled in the following table, Table 1a. Here, as below, six test cells were filled and each individual mixture was studied. The value indicated is the average of six individual values. The relative deviation of the "voltage holding ratio" values in various measurement series is usually in the range of about 3 to 4%. 100 ppm of reference compounds R-1 to R-3

Then add to each of the other three mixtures M-1, and in each case 100 ppm of one of the three compounds 1-1 to 1-3

Add to each of the three other parts of mixture M-1 and the resulting mixtures (C-1.1, C-1.2 and C-1.3, and M-1.1, M-1.2 and M-1.3) are stable as above the study. The results are shown in the following table, Tables 1a to 1d. Table 1a

Table 1b

Table 1c

Table 1d

example 2 . 1 . 1 to 2 . 6 . 3 and corresponding comparative examples The following mixture (M-2) was prepared and studied.

This mixture, Mixture M-2, was investigated below with regard to its stability of voltage retention to irradiation with UV radiation. For this purpose, the mixture is also divided into several portions. First, the stability of the mixture (M-1) itself was determined. To this end, the stability of mixture M-1 to UV exposure was investigated in a test cell with appropriate polyimide as alignment material for planar alignment, a layer thickness of 6.0 μm and a flat ITO electrode. For this purpose, the respective test cells are exposed to sunlight for 30 minutes. In each case, the voltage retention was measured after 5 minutes at a temperature of 100°C. Unless otherwise specified, the addressing frequency (or measurement frequency) herein is 60 Hz. The results are edited in Table 2a. Next, for comparison, 100 ppm, 300 ppm or 600 ppm of reference compound R-2 were added to three parts of mixture M-2 and the resulting mixtures (C-1.1, C-1.2 and C-1.3.) were as above said research. The results are compiled in the table below, Table 2a. As indicated above, 100 ppm, 300 ppm or 600 ppm in each case of one of compounds 1-1 to 1-3, and the following compounds 1-4 to 1-6 will then be added

In each case added to the group of other three-part mixtures M-2 and the resulting mixtures (C-1.1, C-1.2 and C-1.3, and M-1.1, M-1.2 and M-1.3) were studied as described above of stability. The results are shown in the following table, Tables 2a and 2b. Table 2a

It is readily apparent here that compounds 1-1 to 1-6 exhibit significant stabilizing properties even at relatively low concentrations. The studies described above were repeated at a temperature of 60°C and an addressing/measurement frequency of 10 Hz. The results are compiled in the table below, Table 2b. Table 2b

example 3 The following mixture (M-3) was prepared and studied.

Mixture M-3 was also divided into portions as described in Examples 1 and 2 and various compounds were added as such and in test cells with alignment material for planar alignment and planar ITO electrodes to study their exposure to LCD backlights And the stability of UV light source.example 4 The following mixture (M-4) was prepared and studied.

Mixture M-4 was also divided into several portions as described in Examples 1 and 2 and various compounds were added as such and in test cells with alignment material for planar alignment and planar ITO electrodes to study their exposure to LCD backlights And the stability of UV light source.Example 5 The following mixture (M-5) was prepared and studied.

Mixture M-5 was also portioned as described in Examples 1 and 2 and various compounds were added as such and in test cells with alignment material for planar alignment and planar ITO electrodes to study their exposure to LCD backlights And the stability of UV light source.

Claims (18)

A liquid-crystalline medium, characterized in that it comprises a) one or more compounds of the formula I

wherein R ¹¹ at each occurrence independently of one another represents H, F, a straight or branched alkyl chain having 1 to 20 C atoms, one -CH ₂ - group or, if present, a plurality of -CH ₂ A - group can be replaced by -O- or -C(=O)-, but two adjacent -CH ₂ - groups cannot be replaced by -O-, and one or a plurality of -CH ₂ - groups if present Can be replaced by -CH=CH- or -C≡C-, and one H atom or a plurality of H atoms can be replaced by F, OR ¹³ , N(R ¹³ )(R ¹⁴ ) or R ¹⁵ , and R ^{12 is} in each when occurrence independently represents a straight-chain 1-20 C atoms or a branched alkyl chain wherein a -CH ₂ - group or a plurality of -CH ₂ - groups may be replaced by -O- or -C (=O)-, but two adjacent -CH ₂ - groups are not replaceable by -O-; hydrocarbyl, which contains cycloalkyl or alkylcycloalkyl units and in which one -CH ₂ - group or groups The -CH ₂ - group can be replaced by -O- or -C(=O)-, but two adjacent -CH ₂ - groups cannot be replaced by -O-, and one H atom or a plurality of H atoms can be replaced by -O- Replacement with F, OR ¹³ , N(R ¹³ )(R ¹⁴ ) or R ¹⁵ ; or an aromatic or heteroaromatic hydrocarbon group, wherein one H atom or a plurality of H atoms can be replaced with OR ¹³ , N(R ¹³ )( R ¹⁴ ) or R ¹⁵ , R ¹³ independently of one another in each occurrence represent a straight-chain or branched-chain alkyl or acyl radical having 1 to 10 C atoms or an aromatic hydrocarbon or carboxyl radical having 6 to 12 C atoms an acid group, R ¹⁴ in each occurrence independently of one another represents a straight-chain or branched-chain alkyl or acyl group having 1 to 10 C atoms, or an aromatic hydrocarbon or carboxylic acid group having 6 to 12 C atoms, R ¹⁵ at each occurrence independently of one another represents a straight-chain or branched alkyl group having 1 to 10 C atoms, in which one -CH ₂ - group or a plurality of -CH ₂ - groups can be replaced by -O- or -C(=O)-, but two adjacent -CH ₂ - groups cannot be replaced by -O-, S ¹¹ and S ¹² at each occurrence, independently of each other, represent an extension having 1 to 20 C atoms Alkyl, in which one -CH ₂ - group or multiple -CH ₂ - groups if present may be replaced by -O- or -C(=O)-, but two adjacent -CH ₂ - groups may not be Replacement with -O-, and one H atom or a plurality of H atoms may be replaced with F, OR ¹³ , N(R ¹³ )(R ¹⁴ ) or R ¹⁵ , or represents a single bond, and Y ¹¹ to Y ¹⁴ are each independently of each other Denotes methyl or ethyl, Z ¹¹ to Z ¹⁴ independently of one another at each occurrence -O-, -(C=O)-, -O-(C=O)-, -(C=O) -O-, -O-(C=O)-O-, -(NR ¹³ )-, -NR ¹³ -(C=O)- or single bond, if S ¹¹ is a single bond, but both Z ¹¹ and Z ¹² do not simultaneously represent -O-, and if S ¹² is a single bond, then both Z ¹³ and Z ¹⁴ do not simultaneously represent -O-, and if -X ¹¹ [-R ¹¹ ] _o - is a single bond, then Z ¹² and Z ¹³ do not represent -O- at the same time, X ¹¹ represents C, p represents 1 or 2, o represents (3-p), and if p is 2, then n represents the integers 2 to 4, and m represents (4-n), and if p is 1, n represents the integers 3 to 10, and m represents (10-n), and

represents an organic group having (m+n) bonding points, and wherein in the case of p=1, -X ¹¹ [-R ¹¹ ] _o - may alternatively also represent a single bond, and b) one or more Compounds of formula II

wherein R ²¹ represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms ^{, and R 22 represents an unsubstituted alkyl group having 2 to 7 C atoms} alkenyl, and/or c) one or more compounds selected from the group of compounds of formulae III-1 to III-4 and B,

wherein R ³¹ represents an unsubstituted alkyl group ^{having 1 to 7 C atoms, and R 32} represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkane having 1 to 6 C atoms Oxygen, m, n and o each independently of each other represent 0 or 1, R ^B1 and R ^B2 each independently of each other represent unsubstituted alkyl, alkoxy, oxaalkyl having 1 to 7 C atoms or alkoxyalkyl, or alkenyl or alkenyloxy having 2 to 7 C atoms, and L ^B1 and L ^B2 each independently of one another represent F or Cl. The medium of claim 1, wherein the total concentration of the compound of formula I in the medium as a whole ranges from 1 ppm or more to 2000 ppm or less. The medium of claim 1, wherein it comprises a compound of formula II as indicated in claim 1, wherein R ²¹ represents n-propyl and R ²² represents vinyl. The medium of claim 3, wherein the overall concentration of the compound of formula II in the medium is from 25% or more to 45% or less. The medium of any one of claims 1 to 4, wherein it comprises one or more compounds of formula B as claimed in claim 1. The medium of any one of claims 1 to 4, wherein it comprises one or more of the items referred to in claim 1 The compound of formula III-4 is shown. The medium of any one of claims 1 to 4, wherein it additionally comprises one or more chiral compounds. A compound of formula I

wherein the parameters have the meanings as specified in the case of formula I of claim 1. A compound of formula I as claimed in claim 8, wherein p represents 2. The compound of formula I according to claim 9, which is selected from the group of compounds of formula I-1 to I-9

and

An electro-optical display, characterized in that it contains a liquid crystal medium as claimed in any one of claims 1 to 7. The electro-optic display of claim 11, wherein it is based on the IPS, FFS, VA or ECB effect. An electro-optical display as claimed in claim 11 or 12, wherein it contains active matrix addressing means. 10. Use of a compound of formula I as claimed in any one of claims 8 to 10 in liquid-crystalline media. A use of a liquid crystal medium as claimed in any one of claims 1 to 7 in electro-optic displays or electro-optic components. A process for the preparation of liquid-crystalline media as claimed in claim 1, characterized in that one or more compounds of formula I as claimed in claim 1 are combined with one or more compounds of formula II as claimed in claim 1 and/or one or more compounds of formula II Mixtures of compounds selected from the group of compounds of formula III-1 to III-4 as described in claim 1. A method for stabilizing liquid-crystalline media, characterized in that one or more compounds of the formula I as given in claim 1 and optionally one or more compounds selected from the group of compounds of the formulae OH-1 to OH-6 ,

added to the medium. A process for the preparation of a compound of formula I as claimed in any one of claims 8 to 10, characterized in that it contains two 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl alcohols Reacts with ring structures suitable for derivatization.